When a risk becomes an issue, the planned response provides a starting point, but the project manager should remain adaptive and choose the best response based on current information. If a credible alternative response is proposed, the appropriate step is to evaluate it with the project team (A) to confirm feasibility, effectiveness, side effects, and total impact (cost, schedule, quality, residual risks). This aligns with PMP decision-making: analyze options and select the response that best meets project objectives within constraints.
Blindly adhering to the original plan (B) can be wasteful if circumstances have changed or a better option exists. Implementing immediately (C) is improper without validation and authorization; "cheaper" claims may ignore hidden costs or risks. Sending an email to the CCB (D) is premature; change control is appropriate if the selected response requires baseline changes or exceeds authority thresholds, but first the PM should conduct a structured evaluation to determine whether the new response is truly superior and what approvals are required.