[单选题]
Electric dipoles alwvn x5,r3bh -ilg1f xz8ayn16 ,.kdcg:btpav 5qxs consist of two charges that are
A. equal in magnitude; opposite in sign.
B. equal in magnitude; both are negative.
C. equal in magnitude; both are positive.
D. unequal in magnitude; opposite in sign.
