The Linear Multiple Regression Model Can Be Represented in Matrix $\boldsymbol { Y } = \boldsymbol { X } \boldsymbol { \beta } + \boldsymbol { U }$

Multiple Choice

The linear multiple regression model can be represented in matrix notation as $\boldsymbol { Y } = \boldsymbol { X } \boldsymbol { \beta } + \boldsymbol { U }$ where X is of order n x(k+1) . k represents the number of

A) regressors.
B) observations.
C) regressors excluding the "constant" regressor for the intercept.
D) unknown regression coefficients