Wendy Manages Ten Google AdWords Accounts for Her Clients

Wendy manages ten Google AdWords accounts for her clients. She would like to organize her billing so that she makes one payment for the clients account rather than ten individual payments, i.e., one for each client she manages. What approach should Wendy follow in this instance?

A) Google does not allow multiple accounts to be billed to one invoice.
B) Google recommends that Wendy move her accounts into the My Client Center with her cred it card.
C) Google recommends that Wendy enroll in the Manager Defined Spend.
D) Google recommends that Wendy subscribe to the Manager Order-level monthly invoice.