What are $$step$-$downs$$ as it relates to the leverage ratio?

When the lender tightens$/$reduces acceptable adjustments to EBITDA that are used to calculate the leverage ratio

When the lender tightens$/$reduces the borrowing base for debt that is used to calculate the leverage ratio

When the lender tightens$/$reduces the leverage ratio covenant in later years as the borrower pays down debt

When the lender tightens$/$reduces cash interest in later years as the borrower pays down debt