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How can I adjust this venn Diagram so it becomes like what I wrote on the Image below?

I need to Color the "M" rectangle on the third Diagram and to remove the intersection between A and B on the fourth one.

I am using the following codes:

 pgfkeysnot inside/.code=clip[use path=#1,reverseclip];,
 inside/.code=clip[use path=#1];,
 shade/.code=fill[#1] (current bounding box.south west)rectangle 
 (current bounding box.north east);
 begintikzpicture
 draw[thick,fill=white] (-1,0) node$A$ circle [radius=1.5cm]
 (1,0) node[above]$M$ (0,-1.5) node[below]$A^c$;
 draw[frame=5pt];
 endtikzpicture
 begintikzpicture
 draw[thick,save path=pathA,fill=gray] (-1,0) node$A$ circle [radius=1.5cm];
 draw[thick,save path=pathB] (1,0) node$B$ circle[radius=1.5cm];
 path (0,1.5) node[above]$M$
 (0,-1.5) node[below]$A - B$;
 beginscope[on background layer]
 pgfkeysinside/.list=pathB,shade=white
 endscope
 draw[frame=5pt];
 endtikzpicture

And things are ending up this way:

I am sorry if I'm lacking any information, I am very new on LaTeX and I have been trying to do this for quite a while now.

Anyway, Thank you for your attention/help!

documentclassarticle
usepackagetikz
usetikzlibrarybackgrounds
% based on https://tex.stackexchange.com/a/12033/121799
tikzsetreverseclip/.style=insert path=(current bounding box.south west)rectangle 
(current bounding box.north east) , 
use path/.code=pgfsetpath#1,%learned from Kpym
frame around/.style=insert path=
([xshift=-pgfkeysvalueof/tikz/frame
distance,yshift=-pgfkeysvalueof/tikz/frame distance]#1.south west) rectangle
([xshift=pgfkeysvalueof/tikz/frame
distance,yshift=pgfkeysvalueof/tikz/frame distance]#1.north east),
frame distance/.initial=5pt

begindocument
pgfkeysnot inside/.code=clip[use path=#1,reverseclip];,
inside/.code=clip[use path=#1];,
shade/.code=fill[#1] (current bounding box.south west)rectangle 
(current bounding box.north east);
begintikzpicture
 beginscope[local bounding box=TL]
 draw[thick,fill=gray] (-1,0) node$A$ circle [radius=1.5cm]
 (1,0) node$B$ circle[radius=1.5cm] (0,1.5) node[above]$M$
 (0,-1.5) node[below]$Acup B$;
 endscope 
 %
 beginscope[xshift=5.5cm,local bounding box=TR]
 draw[thick,save path=pathA] (-1,0) node$A$ circle [radius=1.5cm];
 draw[thick,save path=pathB] (1,0) node$B$ circle[radius=1.5cm];
 path (0,1.5) node[above]$M$
 (0,-1.5) node[below]$Acap B$;
 beginscope[on background layer]
 pgfkeysinside/.list=pathA,pathB,shade=gray
 endscope
 endscope
 %
 beginscope[yshift=-4.5cm,local bounding box=BL]
 draw[thick,fill=gray,even odd rule] (-0.5,0) node$A$ circle [radius=1.5cm]
 (-2.5,-2) rectangle (2.5,2) node[below left]$M$;
 endscope 
 %
 beginscope[xshift=5.5cm,yshift=-4.5cm,local bounding box=BR]
 pgfresetboundingbox
 draw[thick,save path=pathC] (-1,0) node$A$ circle [radius=1.5cm];
 draw[thick,save path=pathD] (1,0) node$B$ circle[radius=1.5cm];
 path (0,1.5) node[above]$M$ (0,-1.5) node[below]$A- B$;
 pgfkeysnot inside=pathD
 fill[gray,use path=pathC];
 endscope
 %
 foreach X in TL,TR,BL,BR draw[frame around=X];
endtikzpicture
enddocument