Which task would be better suited for a for loop than for a list comprehension?

Choice $1$ of $4$: Finding the largest value in a collection.

Choice $2$ of $4$: For each student in a list of uniqnames, creating the UM email uniqname $+\text{'}$@umich.edu'.

Choice $3$ of $4$: Turning a set of passwords into their encrypted version.

Choice $4$ of $4$: Computing the square roots of all perfect squares in a list of numbers.