Which of the following is the most likely plant response to an ...

[xclash]

Which of the following is the most likely plant response to an attack by herbivores?
A) leaf abscission to prevent further loss
B) early flowering to try and reproduce before being eaten
C) production of chemical compounds for defense or to attract predators
D) production of physical defenses, such as thorns
E) production of thicker bark and cuticle to make it more difficult to eat

[clippers!]

I chose D and got the answer, hope that helps.