Respuesta :
Answer: A) Adenine
Explanation: When paring nitrogen bases there is a rule to be followed; Thymine to Adenine, and Cytosine to Guanine. A-T and C-G. If it helps you remember...
The apple always comes from the tree (Adenine to Thymine)
A car always need gas (Cytosine to Guanine)
Hope this helped!