Extra exam question E7F01

Why"Direct sampling" in a software defined radio means the incoming RF is digitized by an analog-to-digital converter without being mixed with a local oscillator signal. Direct sampling in a software defined radio means the incoming RF signal is fed straight into an analog-to-digital converter and digitized directly, without first being mixed down to a lower frequency by a local oscillator and mixer the way a traditional superheterodyne receiver works, answer C. It isn't about converting software source code during operation, isn't a description of generating I/Q signals purely by digital processing with no RF amplification at all, and doesn't specifically involve a switching mixer generating I/Q directly, those describe other SDR architectures, not direct sampling itself.