Which of the following are the criteria associated with design of sag vertical curve?
1. Provision of minimum stopping distance during day time
2. Adequate drainage
3. Comfortable operation
4. Pleasant appearance
A. 1, 2 and 3
B. 2 and 3
C. 2,3 and 4
D. 1 and 3
Correct answer is option 'C. 2,3 and 4'. Can you explain this answer?