Which of the following is true?

a$.(01{)}^{**}0=0(10{)}^{**}$

b$.(0+1{)}^{**}0(0+1{)}^{**}1(0+1)=(0+1{)}^{**}01(0+1{)}^{**}+$

c$.(0+1{)}^{**}01(0+1{)}^{**}+1**0**=(0+1{)}^{**}x$

d$.$ All of the mentioned