Which of the following REs denote the GTG given above?

a$)b$

b$)(ab{)}^{**}ab+b$

c$)b+(ab{)}^{**}{a}^{**}(a+b)$

d$)(ab{)}^{**}a(a+b)$

Let $,$ def, $y$ and $L_2=\{a,x,y\}.$ Which of the following languages does the

string "defxy" belong to$?$

a$)L_1{L}_2$

b$)L_1{L}_1{L}_2^{**}$

c$)L_2^{**}{L}_1{L}_2^{**}$

d$)L_1^{***}{L}_2$

Let ends in $011$