Its either A or C but im sorry i dont know which one
A strand of DNA having base sequence as ATG CGA. The complementary strand of DNA will be produced with base sequence as TAC GCT. In the double strand DNA nitrogenous bases paired in a specific manner, A (Adenine) always pair with T (Thymine) with double hydrogen bond or vice-versa and C (Cytosine) pair with G (guanine) with triple hydrogen bond or vice-versa.
The instrument that records and measures the seismic waves during an earthquake is a seismograph. It uses the vibration propagated by from the earthquake source's energy. It mainly uses a suspended pen that records the motion between itself and the paper film.