C) The frequency of allele T would decrease and the frequency of allele t would increase.
Explanation:
If the hunter is going after monkeys with tufted tails (TT), the tufted tail monkeys would die out from the new predator, letting the non-tufted tails (tt) increase in population.
As John is testing the effect of temperature on the solubility of sugar in water. To test this, he will measure the amount of sugar dissolved at different temperature level.