Which of the following series is a time series? Et, Et+1, Et+2, Et+3, Et+4, Et+5, ...etc. In which Et indicates the net income of company A for year t. O A, B, C, D, Et. ...etc. In which A+ indicates the net income of company A for year t. At, Bt+1, Ct+2, D++3, Et+4, ...etc. In which A+ indicates the net income of company A for year t, B++1 indicates the net income of company B for year t+1. Et, Et, Ct, Dt, Et, ...etc. In which A+ indicates the net income of company A for year t