The reason why so many children like to eat this new brand of biscuit is that it is particularly sweet and（）

A．Its effect remains to be seen.
B．It serves as a kind of placebo.
C．It proves to be an effective therapy.
D．It hardly produces any effects.

A．Winter depressives prefer light therapy in spite of its inconvenience.
B．Light therapy increases the patient's photosensitivity.
C．Eye damage is a side effect of light therapy.
D．Light boxes can be programmed to correspond to shifts in the body clock.