In a multiple regression model, with variables x1, x2 and x3, which of the following actions wouldmost likelymake the standard error of the slope for x2 decrease? Explain why?

A) Increase the sample size by a factor of two.

B) Decrease the sample size by a half.

C) Remove any points that are leveraged with respect to the x2 variable.

D) Remove x1 and x3 from the model, so long as they are uncorrelated with x2, and then refit.