Step 1: Understanding the Concept:
We need to find the probability of the union of two events A and B.
Step 2: Key Formula or Approach:
The formula for the union of two events is:
\[
P(A \cup B) = P(A) + P(B) - P(A \cap B)
\]
Step 3: Detailed Explanation:
Given: \(P(A) = \frac{1}{2}\), \(P(B) = \frac{1}{3}\), \(P(A \cap B) = \frac{1}{6}\).
\[
P(A \cup B) = \frac{1}{2} + \frac{1}{3} - \frac{1}{6} = \frac{3}{6} + \frac{2}{6} - \frac{1}{6} = \frac{4}{6} = \frac{2}{3}
\]
Step 4: Final Answer:
Therefore, option (D) is correct.