Which of the following are the factors of 75?

The given number is 75.
Finding the factors of 75:
$\begin{array}{l}75=1\times 75 \\ 75=3\times 25 \\ 75=5\times 15 \end{array}$

$\begin{array}{l}75=15\times 3 \\ 75=25\times 3 \\ 75=75\times 1 \end{array}$
Therefore, the factors of 75 are 1, 3, 5, 15, 25, and 75.