As shown in the accompanying figure, a closed envelope icon appears for an unread message.

The basic generic functional interface ________ in package java.util.function contains method get that takes no arguments and produces a value of type T. Often used to create a collection object in which a stream operation’s results are placed.

a. Consumer b. Function c. Supplier d. BinaryOperator

____________ XML Invoice Specification enables business customers to exchange creditcard purchase information over the Internet in a secure standardized form.

Fill in the blank(s) with the appropriate word(s).