(5) Although the exact cause is not known, gastrointestinal problems will result after a pet ingests grapes or raisins.

Choose the BEST revision of sentence (5).

A)
Although the exact cause is not known, gastrointestinal problems result after a pet ingests grapes or raisins.

B)
Although their exact cause is not known, gastrointestinal problems result after a pet ingests grapes or raisins.

C)
Although the exact cause is not known, gastrointestinal problems can result after a pet ingests grapes or raisins.

D)
Although their exact cause is not known, gastrointestinal problems can result after a pet ingests grapes or raisins.