Answer:
A-C
Step-by-step explanation:
Hello There!
Remember these are the complementary base pairs
Adenine and Thymine (so the 2nd and 4th one are correct base pairs)
Cytosine and Guanine ( so the 3rd one is a correct base pair)
Hence, A-C would be the incorrect base pair because like stated previously Adenine pairs with thymine not cytosine