Total people that took the survey = 150
People who consider global warming as threat = 50% = 50/100 * 150 = 75
75 people do not consider global warming as threat

Target question => How many of the representatives were male?

Statement 1 => In the survey, 60 women concluded global warming as the biggest threat to earth
From the 75 people that took global warming as threat, 60 are women and 15 are men but from the remaining 75 people that do not consider global warming as threat, we don't know the number of men and women count. Therefore, the total male representatives cannot be evaluated and statement 1 is NOT SUFFICIENT.

Statement 2 => Among the representatives, 66.67% of women and 25% of men concluded global warming as the biggest threat to earth
From question stem => male + female = 150
From this statement, 66.67% of female and 25% of male = 75
m + f = 150
0.667f + 0.25m = 75

$$f=150-m$$
$$0.667(150-m)+0.25m=75$$
$$100.05-0.667m+0.25m=75$$
$$100.05-0.417m=75$$
$$-0.417m=75-100.05$$
$$\frac{-0.417m}{-0.417}=\frac{-25.05}{-0.417}$$
$$m=60.07$$
$$m\approx60$$
$$Statement\ 2\ alone\ is\ SUFFICIENT$$
$$Answer\ =\ B$$