Charges `Q_1 and Q_2` lie inside and outside, respectively, of a closed surface S. Let E be the field at any point on S and `phi` be the flux of E over S.
A. If `Q_1` changes, both E and `phi` will change.
B. If `Q_2` changes, E will changes but `phi` will not change.
C. If `Q_1 = 0 and Q_2 !=0`, then `E!= 0 but phi = 0`
D. If `Q_1 = 0 and Q_2 !=0`, then `E= 0 but phi != 0`