C,D and F are correct.
C is what you would think of when reading it, you walked 12 and walked 1/4(12) more.
12 + 12(1/4) =
12 + 3 =
15
D is equal to C when simplified,
12(1+1/4) =
12 + 3 =
15
F is the same as the D, it just simplified the numbers in the parenthesis
12(1+1/4) =
12(4/4 + 1/4) =
12(5/4) =
15
It would be mean. The mean is the average that is you are looking for, since she wants a summerization of all the values in the data set. To find the mean (average) add all the numbers and then divide by the amount of numbers.
I think your answer is y=-4/7x+5
Is point B.
Because √3≈1.7.
So it should be B.