Answer:
A. add -15 and 9
Step-by-step explanation:
We follow the PEMDAS rule as the order of operations to evaluate expressions.
P-Parenthesis
E-Exponents
M-Multiplication
D-Division
A-Addition
S-Subtraction
Given expression : 
In order to evaluate the expression, the first step would be to do the parenthesis operations which requires to add -15 and 9.
The only correct answer would be A because of the following reasons
1. Sin is defined as opposite/hypotenuse
2. Cos is defined as adjacent/hypotenuse
To find the average, add the cost of each book to get a total cost, then divide the total cost by the number of books purchased.
Total cost: 32 + 45 + 39 = 116
Average cost: 116 / 3 = 38.67
1,060 ÷ 5 = 212. He picked 212 blueberries from each row