The possibile answer is 10 ÷ 6 = 1.6
The answer C make more sense.
You can solve this by setting up a proportion. The number of men over the number of women.
3/4 = 210/x Cross multiply
3x = 4(210) Multiply
3x = 840 Divide
x = 280
When there are 210 men, there are 280 women.