Int $x=6$; int$*$ptr$=$&x;

one of the following statements is error:

a$.$ cout $$&${?}^{**}x$;

b$.$ cout &$x$;

C$.$ cout $<mi\; id="EditorElement\_3528167">*</mi><mi\; id="EditorElement\_3528169">*</mi>$& ptr;

d$.$ cout $$&${?}^{**}$ ptr;