C- is either a or c
Explanation -
If you divide 21/49 by 7 you get 3/7
Let
y-------> number of books read during the month 
x------> number of picture of a book
we know that

in this problem
for 
calculate y

therefore
the answer is
The number of books read during the month
is 
Answer:
Ryan's new employer has offered him a few insurance plans as part of his employee benefits package.
Step-by-step explanation:
Ryan is working as deputy manager in a company. He currently has salary and there are no additional benefits. He is currently having only health insurance. When he joins the new company he gets few insurance plans as part of employee benefit packages. This is additional benefits which attracts a candidate to join a company and it keeps the employees motivated.
3c-d
3c-(-c+7)
3c+c-7
4c-7
Final answer: 4c-7