请选择DCBA4`:@6|:b3g6j+n(S-t0c Birds ________ when there isn’t enough food for them．3j;q6W:y5j/G1g7u/n
A． starve3j;q6W:y5j/G1g7u/n
B．are starving3j;q6W:y5j/G1g7u/n
C．starved3j;q6W:y5j/G1g7u/n
D．starves3j;q6W:y5j/G1g7u/n