What are three characteristics of valid Ethernet Layer 2 addresses? (Choose three.)

They are 48 binary bits in length.
They are considered physical addresses.
They are generally represented in hexadecimal format.
They consist of four eight-bit octets of binary numbers.
They are used to determine the data path through the network.
They must be changed when an Ethernet device is added or moved within the network.

ccna exploration 1 chapter 7 Exam Question And Answers 

What are three characteristics of valid Ethernet Layer 2 addresses? (Choose three.)