Which of the following represents a grazing food chain?
a. leaves $\rightarrow$ detritus feeders $\rightarrow$ deer $\rightarrow$ owls
b. birds $\rightarrow$ mice $\rightarrow$ snakes
c. nuts $\rightarrow$ leaf-eating insects $\rightarrow$ chipmunks $\rightarrow$ hawks
d. leaves $\rightarrow$ leaf-eating insects $\rightarrow$ mice $\rightarrow$ snakes