If 213 × 16 = 3408, then 16 × 21.3 is equal to :
Choices:
A) 0.3408 B) 3.408 C) 34.08 D) 340.8 E) none of these

Rationale: "solution 16 × 21.3 = ( 16 x 213 / 10 ) = ( 16 x 213 / 10 ) = 3408 / 10 = 340.8 . answer d"
Answer: D