In a Multiple Regression, the Dependent Variable Is House Value

In a multiple regression, the dependent variable is house value (in '000$) and one of the independent variables is a dummy variable, which is defined as 1 if a house has a garage and 0 if not. The coefficient of the dummy variable is found to be 5.4 but the t-test reveals that it is not significant at the 0.05 level. Which of the following is true?

A) A garage increases the house value by $5,400.
B) A garage increases the house value by $5,400, holding all other independent variables constant.
C) The house value remains the same with or without a garage.
D) We need to include other dummy variables.