—The two girls are 　　　　 to go to school by themselves.

—I agree with you. They can take care of 　　　　.

A．enough old; one another

B．old enough; each other

C．enough old; themselves

D．old enough; them

火焰迸人阻火器时，阻火器会切断燃料气使火焰熄灭。