Which of the following operating activities is supported by digital mode software in the WSJT-X software suite?

Explication

The WSJT-X suite includes purpose-built modes for each of these weak-signal paths: JT65 and Q65 for Earth-Moon-Earth, WSPR for propagation beacons, and MSK144 for the very short reflections of meteor scatter. All three are supported, so the combined choice is correct.