Confused between option 'b' and 'd'. Since adjusted R2 cannot be greater than R2, so even if insignificant varibable is taken out, the adjusted R2 value will increase but not more than R2 value which is 0.594. Do help

Q) The number of computers assembled by a firm each month is associated with the number of unskilled labor hours used, the number of skilled labor hours used and the kilowatt-hours (KWH) of power used by the assembly operations. A multiple regression model with Log transformation of all variables is used to explain the Log of numbers of computers shipped per month. The results of the regression are as follows:

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