An increase in which of the following could increase long-billed curlew population?

A. milkweed
B. pesticide use
C. grassland habitats
D. forest habitats

C. grassland habitats

Long-billed curlews prefer grassland habitats for nesting and foraging. Increasing grassland habitats could provide more suitable areas for the long-billed curlew to thrive and potentially increase their population.