The answer is C) more offspring that can survive and reproduce.
In order for a population to survive, there must be enough offspring at least to maintain the number of population. It is better if there are more offspring able to survive and reproduce and species evolved different strategies to achieve this, such as care for the offspring.
On the other hand, neither more males nor more females will help a population to survive. There will be no variability in a gene pool because one male will cross with many females and vice versa. And with greater variability of characteristics, the greater is the chance to survive. Also, a large number of self-fertilized individuals could not be the right answer because this is an example of asexual (self-fertilization) reproduction.