Someone who is very shrewd could be described as. a porcine b. ursine c. vulpine d. lupine

Well, the definition of shrewd is severe, basically.

Porcine means relating to pigs.

Ursine means relating to bears.

Vulpine means relating to foxes.

Lupine means relating to wolves.

So, bears, foxes, and wolves are shrewd.

Wolves are the most shrewd.

So, someone who is shrewd could be described as lupine.