Which of the following types of signals can be relayed through a linear transponder?
Why A linear transponder does not demodulate anything. It receives a whole slice of spectrum, amplifies it linearly, and translates it to a different output band, preserving the amplitude, frequency and phase relationships of everything inside that passband. Because the modulation is never touched, any mode that fits in the passband comes out the other side intact: CW, SSB, FM, SSTV, PSK and packet alike. Contrast this with an FM repeater-style transponder, which demodulates one FM signal and retransmits it, so only that mode works.
Watch out Each single-mode choice is tempting because operators mostly use CW and SSB on linear birds, and wide FM signals are discouraged since one hogs power from the shared transponder, but discouraged is not the same as impossible.
Linear = mode-transparent: it moves spectrum, not messages, so every mode rides through.