An analyst observes a positive relationship between digital marketing expenses and online sales for a firm. However, she intuitively feels that she should add an additional predictor variable, one which has a high correlation with marketing expenses. If the analyst adds this independent variable to the model, which of the following could happen? More than one choices could be correct.

Options -
1)The model’s R-squared will decrease
2)The model’s adjusted R-squared could decrease
3)The Beta-coefficient for predictor - digital marketing expenses, will remain same
4)The relationship between marketing expenses and sales can become insignificant