If 10a = 6b = 20, then 120ab =  Choose the correct choice from the following answers:
A) 800 B) 1000 C) 1200 D) 1400 E) 1600

Rationale: "10 a * 6 b = 20 * 20 = 400 60 ab = 400 i . e . 120 ab = 800 answer : option a"
Answer: A