Which formula finds the correct Euclidean distance?

You are attempting to find the Euclidean distance between two centroids:

Centroid A’s coordinates: (X = 2, Y = 4)

Centroid B’s coordinates (X = 8, Y = 10)

Which formula finds the correct Euclidean distance?
A . SQRT((2-8)2+(4-10)2) or 8.49
B . SQRT(((2-8) x 2) + ((4-10) x 2)) or 12.17
C . ((2-8)2+(4-10)2) or 72
D . ((2-8) x 2 + (4-10) x 2) or 148

Answer: A