For this case we have that by definition, a variable is a symbol that can be replaced or that takes a numerical value in an equation or expression, mathematical in general.
Then we have the following options:
A) 
It is a sum of two real numbers. There are no variables.
B)
In this case the variable is "d"
C) 
In this equation, the variable is represented by "r"
D) 
It is a sum of two real numbers. There are no variables.
Answer:
A) There are no variables
B) "d"
C) "r"
D) There are no variables
Plug in the two points into the distance formula (if you don't know what the formula is, search it up)
Answer:
the answer is 8.83 inches per piece, the 2 whole numbers it lies between are 8 and 9
Step-by-step explanation:
53/6= 8.83