Your Service Provider does not support Link Fragmentation and Interleave, but upstream serialization delay on your broadband link is affecting voice quality. Which two mitigation strategies are viable?（）

• A、Upgrade your residential broadband service to at least 768kbps uplink.
• B、Switch your home router to use PPP encapsulation.
• C、Use the ip tcp adjust-mss interface command.
• D、Employ QoS techniques to drop large data packets.
• E、Use traffic shaping to interrupt large data packets.