Choose the correct answer that complete thes...

Câu hỏi: Choose the correct answer that complete these given words.

A. Laser is a device which concentrates light waves into an intense light beam.

B. The laser is a device which concentrates light waves and an intense light beam.

C. Laser is a device concentrates light waves into an intense light beam.

D. The laser is a device to concentrate light waves to an intense light beam.