If $S_{n}$ Denotes Your Total Earnings After $n$ Weeks of Work, What Is the Average Amount of Money

If $S_{n}$ denotes your total earnings after $n$ weeks of work, what is the average amount of money you earned each week for the first 14 weeks?

A) $\sum_{i=1}^{14} S_{i}$
B) $\frac{1}{14} \sum_{i=1}^{14} S_{i}$
C) $14 S_{14}$
D) $S_{14} / 14$