Answer
60Hz, 120Hz, 180Hz.
Work Step by Step
The frequencies of the harmonics for a string that is fixed at both ends are given by equation 11-19b.
$$f_n=nf_1$$
“Four loops” is the standing wave pattern for the fourth harmonic, $240Hz=f_4=4f_1$.
Therefore, other resonant frequencies include $f_1=60Hz$, aka the fundamental or the first harmonic, $f_2=2 \times 60Hz=120 Hz$, aka the first overtone or the second harmonic, and $f_3=3 \times 60Hz=180 Hz$, aka the second overtone or the third harmonic.