80. A small object with charge q and weight mg is attached to one end of a string of length L . The other end is attached to a stationary support. The system is placed in a uniform horizontal electric field E, as shown in the accompanying figure. In the presence of the field, the string makes a constant angle q with the vertical. What is the sign and magnitude of q?
(A) positive with magnitude Emg
(B) negative with magnitude Emg
(C) positive with magnitude Emgtanθ
(D) negative with magnitude Emgtanθ