Read the following context and choose the best option to answer the question.
Context: our department is budgeted for 5 people and we have 10 . ugh . it 's lame . i ' ve been picking up shifts that coworkers do n't want / if they call out sick . i ' m basically on call for the next 2 weeks .
Question: What may be the reason I will be on call ?
Options: 
A. I will be on vacation .
B. We will be really understaffed .
C. I will be studying .
D. It is policy


B