Find out one-sevenths of 1.4 million, you get 200,000.
Hence, A is the only option which is lower than 200,000.
However, if you still do not understand, we can use this method:
Let number of cases of women = ‘n’
Therefore, number of cases in men = n + 0.5n = 1.5 n
Total number of cases = 1n + 1.5 n = 2.5n = 200,000
n= 200,000/2.5 = 80,000
Number of cases in men = 80,000 + (0.5×80,000) = 120,000