Define the points Q(x1, y1) and R(x2, y2). Carry out the following calculation: find the unit vector with the same direction as vector QR.

a) Vector QR divided by the magnitude of vector QR
b) Vector QR divided by twice the magnitude of vector QR
c) Twice vector QR divided by the magnitude of vector QR
d) Vector QR divided by the square root of the magnitude of vector QR