Robert is collecting books to donate to the library.
The number of books he collects, nn, is defined by n=14d+21 where d is the number
of days he spends collecting books.
What does 14 represent in the context of Robert's book collecting?
A represents the number of books per day that are collected.
B represents the number of books per week that are collected.
C represents the number of books per month that are collected.
D represents the number of books per year that are collected.

Number 6 btw