In a Waiting Line Situation, Arrivals Occur, on Average, Every $\lambda$

Multiple Choice

In a waiting line situation, arrivals occur, on average, every 10 minutes, and 10 units can be received every hour. What are $\lambda$ and $\mu$ ?

A) $\lambda$ = 10, $\mu$ = 10
B) $\lambda$ = 6, $\mu$ = 6
C) $\lambda$ = 6, $\mu$ = 10
D) $\lambda$ = 10, $\mu$ = 6