3 days
7 days
14 days
21 days
Answer is Wrong!
Answer is Right!
The correct answer is: C. 14 days.
The formwork can be removed from beams after 14 days of concrete pouring. This is because concrete needs 14 days to gain 70% of its compressive strength. Removing the formwork before this time can result in the concrete cracking.
Option A is incorrect because 3 days is not enough time for the concrete to gain enough strength. Option B is incorrect because 7 days is not enough time for the concrete to gain enough strength. Option D is incorrect because 21 days is too long to wait to remove the formwork.