Write a question about the following article.

I even snuck in a trip to the cake decorating store , but was disappointed they were out of everything I need for a cake . Thankfully it 's not for a few weeks , so hopefully they 'll get what I need in . Sunday we went to Front Royal and went canoing on the river with a large group . It was fun , mostly . I ' m very sore in the back and shoulders today , however .

Question:
Why am I in pain today ?

a). Because I overindulged in birthday cake .
b). Because I got into a fight at a store .
c). Because I 'm unused to rowing .
d). None of the above choices .