If three workers are assigned to a task lasting four days, two workers are assigned a task lasting three days, and one worker is assigned to a task lasting three days. The tasks can be completed independently of each other. If you are to schedule with a resource$-$limit$,$ what is the minimum resource limit for the project?

Question $28$ options:

Three workers per day

$21$ worker$-$days

Seven days

Additional information is needed to determine the minimum number.