the correct answer would be D- CAT GT
the reason why D would be the correct answer is because guanine pairs up with cytosine and as for thymine ,it pairs up with adenine so when looking at the complementary strands of DNA ,you would just switch it out for its other half so
Guanine=Cytosine
Cytosine=Guanine
Adenine=Thymine
Thymine=Adenine
