[3%] Assume that the bloom filter has 3 hash functions $f_1(k)$, $f_2(k)$, and $f_3(k)$:

$f_1(k) = (3k) \bmod m,\quad f_2(k) = (2k+1) \bmod m,\quad f_3(k) = k^2 \bmod m,$

where $k$ represents the key and $m$ is the size of bit array for the bloom filter. Which of the following statements is true?