Multiple Choice Question (MCQ)

Question: What is the compressive strength of 150 mm cube at 28 days ordinary concrete of grade M20?
A. 15 N/mm<sup>2</sup>
B. 20 N/mm<sup>2</sup>
C. 25 N/mm<sup>2</sup>
D. 30 N/mm<sup>2</sup>
Correct Answer: 20 N/mm<sup>2</sup>