Which of the following is not a billing option in Campaign Manager?

Quarterly Invoicing is not a standard billing option available in LinkedIn Campaign Manager. Campaign Manager primarily offers Monthly Invoicing for eligible accounts (often larger advertisers with established credit) and Credit Card payments, which is the most common and readily available option for all advertisers. While some direct sales agreements with LinkedIn might involve different payment terms, these are typically outside the self-serve Campaign Manager interface. Therefore, for general use within Campaign Manager, quarterly billing is not an option.