Look at the formula ROE = ROA*EM, and think of two ways to increase ROE. Which is easier?

Increasing EM is easier,since it can be done by simply granting more loans or buying back shares.

Increasing EM is easier,since it can be done by simply issuing more equity.

Increasing ROA is easier,since it can be done by simply choosing higher return assets with the same risk profile.

Increasing ROA is easier,since it can be done by simply raising the interest rates on loans.