When designing a WAN that will be carrying real-time traffic, what are two important reasons to consider serialization delay? (Choose two )

A: Serialization delays are invariable because they depend only on the line rate of the interface B: Serialization delays are variable because they depend on the line rate of the interface and on the type of the packet being serialized. C: Serialization delay is the time required to transmit the packet on the physical media. D: Serialization delays are variable because they depend only on the size of the packet being serialized E: Serialization delay depends not only on the line rate of the interface but also on the size of the packet