Interpolation and decimation
It seems to me that the only way in which one of those solutions is possible is without aliasing. Probably there is a typo error, and the actual sampling rate is greater than 36 kHz. In such a case, for example, if the sampling rate was actually 37 kHz, we can interpolate with a factor I = 4, and then decimate with a factor D = 3 (in that order):
$$
f' = f / I = 18.0~kHz / 4 = 4.5~kHz; \\
f'' = f' \times D = 4.5~kHz \times 3 = 13.5~kHz
$$
Where $f'$ is the frequency component after interpolation, and $f''$ is the frequency component after decimation. Therefore, my final solution is (d) if, and ONLY if, there is a typo and the sampling rate ($f_s$) is actually greater than the Nyquist frequency: $$f_s &gt; f_{Nyquist} = 2\times f = 2\times 18.0~kHz = 36.0~kHz$$.