Answer:
A. Unit rate.
Step-by-step explanation:
We have been given a statement and we are supposed to choose the correct option for our given statement.
Statement:
A constant of proportionality can also be considered a(n) <u> </u> .
Since we know that constant of proportionality represents the amount by which two proportional quantities vary.
Two quantities are directly proportional, when they are in form
, where k represents the constant of proportionality.
We can represent this proportion also as: 
Since k represents the quotient of y and x, so the value of k represents the unit rate for two quantities y and x, therefore, a constant of proportionality can also be considered an unit rate.
Your Answer Is $7.50 Because 3/4 Of $10 Is $7.50