[" (d) The gatche form has two stereogentc centers,and the ant has only one "],[" 0.Which of the following will show optical activity? "],[[bar(Xi)," COOH "],[" (A) "," (B) "],[" (E) "50/50" mixture of "C" and "D," COOH "],[" (a) "A,D" and "E," (b) "A" and E only "],[" Among the structure shown below,which has lowest potential energy? "]]