Which two statements about the IPv4 ToS byte are true?

Which two statements about the IPv4 ToS byte are true? (Choose two.)

A.
The ToS byte is located in the Layer 2 header.

B.
The ToS byte is located in the Layer 3 header.

C.
The DSCP values range from 0 to 7.

D.
The IP precedence and the DSCP fields have two overlapping bits.

E.
The class selector in the DSCP field is defined for backward compatibility with IP precedence.