Which of the following are alternative names for the independent variable (usually denoted by x) in linear regression analysis?

(i) The regressor

(ii) The regressand

(iii) The causal variable

(iv) The effect variable
(A)(ii) and (iv) only (B)(i) and (iii) only (C)(i), (ii), and (iii) only (D)(i), (ii), (iii), and (iv)
B