Answer : Option B

Explanation :

For State Q:

Male population below poverty line = 2.4 million.

Let the female population below poverty line be x million.

 Then, 3 : 5 = 2.4 : x          x = $\frac { 5*2.4 } { 3}$ = 4 

 Total population below poverty line = (2.4 + 4) = 6.4 million.

If N_q be the total population of State Q, then,

25% of N_q = 6.4 million          N_q  = [ $\frac { 6.4*100 } { 25 }$ million = 25.6 million.

For State T:

Male population below poverty line = 6 million.

Let the female population below poverty line be y million.

Then, 5 : 3 = 6 : y          y = $\frac { 3*6 } { 5 }$ = 3.6 

 Total population below poverty line = (6 + 3.6) = 9.6 million.

If N_t be the total population of State T, then,

15% of N_t = 9.6 million          N_t = [ $\frac {9.6 *100 } { 15 }$ ] million = 64 million 

Thus, Required ratio = $\frac { N q } { Nt }$ = $\frac { 25.6 } {64}$ = 0.4 = $\frac {2} { 5 }$