Select the corresponding number (1, 2, or 3) of the arrow type in that best or most closely matches the definition. Same arrow type maybe be used more than once and all arrow types will be used.

____ Sender is unable to perform other tasks until receiver responds.

____ Usually paired with a synchronous message.

____ Message type used with a callback.

____ Message type in which the sender is not blocked until the receiver responds.

1. Type A

2. Type B

3. Type C

Type A Type B