Final answer:
Bluetooth is the wireless standard that relies on direct client-to-client handshake pin code authorization for establishing transmission connection.
Step-by-step explanation:
The wireless standard that depends on direct client-to-client handshake pin code authorization for establishing transmission connection is D. Bluetooth.
Bluetooth is a wireless technology that operates in the 2.4-GHz range and allows devices to communicate with each other over short distances. When two Bluetooth devices want to establish a connection, they perform a secure handshake using a pin code. This pin code authorization ensures that only authorized devices can establish a transmission connection.