Concept:For a regular polygon with n sides, each interior angle is given by n(n−2)×180∘.Explanation:Here, the interior angle is 168∘.So, 168=n(n−2)×180.Multiply both sides by n: 168n=180(n−2).Expand: 168n=180n−360.Rearrange: 168n−180n=−360.This gives −12n=−360.Thus, n=−12−360=30.So, the polygon has 30 sides.Answer:n=30Correct option: B. 30