Following is the Project Evaluation and Review Technique $($ PERT $)$ ?network used to execute a marketing campaign at TeaTime Inc. Calculate the variance for the project.

Group of answer choices

$4\mathrm{.}0$ ?weeks

$2\mathrm{.}5$ ?weeks

$3\mathrm{.}0$ ?weeks

$3\mathrm{.}5$ ?weeks