Step 1: Use Vieta's Formulas.
For a quadratic polynomial:
\[
P(x) = x^2 - (\text{sum of roots})x + (\text{product of roots}),
\]
where the sum of the roots is \( \alpha + \beta = 6 \) and the product is \( \alpha \beta = 4 \).
Step 2: Substitute the values.
\[
P(x) = x^2 - 6x + 4.
\]
Step 3: Analyze the options.
Option (1): \( x^2 - x - 6 \) — Incorrect.
Option (2): \( x^2 + x - 6 \) — Incorrect.
Option (3): \( x^2 - 6x + 4 \) — Correct.
Option (4): \( x^2 - 6x + 4 \) — Correct.
Step 4: Final Answer.
\[
\boxed{x^2 - 6x + 4}
\]