Assume that the Measurable interface is defined with a static sum method that computes the sum of the Measurable objects passed in as an array, and that BankAccount implements the Measurableinterface. Also assume that there is a variable branchAccounts that is an object reference to a populated array of BankAccount objects for a bank branch. Which of the following represents a correct invocation of the sum method to find the total balance of all accounts at the branch?

a. Arrays. sum(branchAccounts)
b. Measurable. sum(branchAccounts)
c. BankAccount. sum(branchAccounts)
d. branchAccounts. sum()