Choice B is the best answer. This question tests comma usage with contrasting phrases.

1. Context clues: "Not haste" contrasts with "patience."
2. Meaning: Use a comma before contrasting phrases beginning with "not."
3. Verify: "The solution requires patience, not haste" correctly shows the contrast.

💡 Strategy: Use a comma before contrasting elements introduced by "not," "but," or "rather than."

Choice A is incorrect because a dash provides more dramatic separation than needed. Choice C is incorrect because a semicolon requires two independent clauses. Choice D is incorrect because a colon introduces lists or explanations, not contrasts.