Which of the following fields precedes the Destination field in an Ethernet header?

In an Ethernet header, the field that precedes the Destination field is the Preamble. The Preamble is a 7-byte field used to signal the start of an Ethernet frame and helps devices on a network synchronize their clocks. It provides a series of alternating 1s and 0s, allowing receiving devices to recognize and prepare for the incoming frame data.

This is critical for ensuring that devices correctly interpret the start of the frame transmission. Following the Preamble, the Destination field identifies the MAC address of the intended recipient device.

While the other fields mentioned play important roles in the Ethernet frame structure, they do not come before the Destination field. For instance, the Source Address identifies the sender and comes after the Destination field, while the Type/Length field describes either the type of protocol being used or the length of the data field, and it follows the Source Address. The Start Frame Delimiter (SFD) serves as a marker indicating the end of the Preamble but is technically part of the Preamble. Thus, the Preamble is the field that correctly precedes the Destination field in the Ethernet header.