4. In a habitat of a semi-aquatic bird population, there are two groups of birds in the population that differ in leg length and diet. Long-legged birds eat fish, while short-legged birds eat insects. A drought hits this habitat causing all of the ponds to dry up, and fish populations decline. The drought has no effect on insect populations. Due to these environment changes, long-legged birds will ____ and short-legged birds will ____.

a. not struggle to survive and increase in population size
b. struggle to survive and decrease in population size

c. struggle to survive and decrease in population size, while short-legged birds may have an advantage and increase in population size.