It’s tiring to sit in front of the computer...

Câu hỏi: It’s tiring to sit in front of the computer for hours.

A. Sitting in front of the computer for hours is tiring.

B. Sit in front of the computer for hours is tiring.

C. Sat in front of the computer for hours is tiring.

D. To sit in front of the computer for hours is tiring.