What Does the Least Squares Method Do Exactly

What does the least squares method do exactly?

A) Minimizes the distance between data points
B) Finds the least problematic regression line
C) Finds those (best) values of the intercept and slope that provide us with the smallest value of the residual sum of squares
D) Finds those (best) values of the intercept and slope that provide us with the smallest value of the sum of residuals