challenging multiple choice question

[yousef]

salam...

honestly i tried ,,, but of no use ,,, so any ideas??

 

[Mohamed123456789]

Is the answer D?

 

[yousef]

Is the answer D?

right .. if u explain that will be great..

 

[Queens]

right .. if u explain that will be great..

The concept of complementary base pairs is used here:
A goes with U.
C goes with G.

part of Sickle cell haemoglobin has 4 amino acids (thr-pro-val-glu)

As Options A, B , C all show complementary bases of the amino acids needed for sickle cell (A-proline , B-glutamine, C-theonine) they are not the answers. The bases in D match none of the bases need for the 4 concerned acids so D is the answer.