We can also solve this using algebra.

Let M = the TOTAL number of males in the country
Let F = the TOTAL number of females in the country
So, the TOTAL population = M + F

60% of the male citizen and 70% of the female citizen are eligible to vote.
0.6M = number ELIGIBLE male voters
0.7F = number ELIGIBLE female voters

70% of male citizens eligible to vote voted, and 60% of female citizens eligible to vote voted.
Number of males who actually VOTED = 70% of 0.6M = 0.7(0.6M) = 0.42M
Number of females who actually VOTED = 60% of 0.7F = 0.6(0.7F) = 0.42F

What fraction of the citizens voted during the election?
Fraction = (number of people who actually VOTED)/(TOTAL population)
= (0.42M + 0.42F)/(M + F)
= (0.42)(M + F)/(M + F)
= 0.42

Answer: A

Cheers,
Brent