Zrjydtj

Can someone show me how to shade the yellow region by modifying my code?
Thank you in advance guys :)

documentclass[]article
usepackage[margin=0.5in]geometry
usepackagepgfplots
renewcommandthesectionarabicsection
usepackagemathtools
usepackagecancel
usepackagepgfplots
usepackageamsmath
newtheoremtheoremTHEOREM
newtheoremproofPROOF
usepackagetikz
usepackageamssymb
usetikzlibrarypatterns
usepackagefancyhdr
usepackagebigints
usetikzlibraryangles
usepackagetcolorbox
usepackagecolor,xcolor
usepackagebooktabs,array
usepackagehyperref
usepackagegraphicx
usetikzlibraryarrows
usepackagepolynom
usepackagewallpaper
usetikzlibraryshapes.geometric
usepgfplotslibraryfillbetween
newenvironmenttightcenter
setlengthtopsep0pt
setlengthparskip0pt
begincenterendcenter
begindocument
begintikzpicture
draw[thick] (-3,-3.9) rectangle (4,2);
draw[thick] (0,0) circle (1.5cm);
draw[thick] (1.5,0) circle (1.5cm);
draw[thick] (0.75,-1.6) circle (1.5cm);
%
%scope
%clip (-3,-2) rectangle (4,2)
%(0,0) circle (1.5cm);
%fill[gray] (1.5,0) circle (1.5cm);
%endscope
%
node [above] at (-3.1,2)$mathcalE$;
node at (-1.2,1.5) $A$;
node at (+2.6,1.5) $B$;
node at (+0.75,-3.4) $C$;
endtikzpicture
enddocument

Straightforward with reverseclip.

documentclass[tikz,border=3.14mm]standalone
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) 
begindocument
begintikzpicture
draw[thick] (-3,-3.9) rectangle (4,2);
draw[thick] (0,0) circle (1.5cm);
draw[thick] (1.5,0) circle (1.5cm);
draw[thick] (0.75,-1.6) circle (1.5cm);
node [above] at (-3.1,2)$mathcalE$;
node at (-1.2,1.5) $A$;
node at (+2.6,1.5) $B$;
node at (+0.75,-3.4) $C$;
beginscope[on background layer]
clip (0,0) circle (1.5cm) [reverseclip];
clip (1.5,0) circle (1.5cm);
fill[yellow] (0.75,-1.6) circle (1.5cm);
endscope
endtikzpicture
enddocument