When a positive charge q is placed in the field created by two other charges Q1 and Q2, each a distance r away from q, the acceleration of q is

Select one:

a. in the direction of the charge Q1 or Q2 of greater magnitude.
b. in the direction of the negative charge if Q1 and Q2 are of opposite sign.
c. in a direction determined by the vector sum of the electric fields of Q1 and Q2.
d. in the direction of the charge Q1 or Q2 of smaller magnitude.
e. in the direction of the positive charge if Q1 and Q2 are of opposite sign.