Given the project's established risk-driven test approach, the most professional and effective response to a shortened schedule is to intensify this strategy. Prioritizing test execution based on the highest product risks ensures that the most critical and impactful areas of the system are validated within the limited time. This maximizes the value of the testing effort by focusing resources where potential failures would have the most severe consequences. Tracking these risks provides essential data to stakeholders, enabling them to make an informed decision about the product's release readiness and to understand the residual risk.

B. Removing testers is counterproductive; it would further reduce the team's capacity to perform essential testing and increase project risk.

C. Automating all remaining manual tests mid-execution is a significant undertaking that requires substantial time and resources, making it unfeasible as a response to a sudden deadline change.

D. Taking no action and simply testing randomly is an unprofessional approach that fails to strategically address the increased risk resulting from the compressed schedule.

---

1. ISTQB® Certified Tester Advanced Level Syllabus, Test Manager, Version 3.1.2 (2023).

Section 3.2.2, Risk-Based Testing: This section explicitly states that a key objective of risk-based testing is to "Prioritize tests during execution, for example, running the most important tests first." It further clarifies its use to "decide which tests to run when there is not enough time to run all planned tests." This directly supports prioritizing tests for the highest product risks when time is constrained.

2. Pressman, R. S., & Maxim, B. R. (2020). Software Engineering: A Practitioner's Approach (9th ed.). McGraw-Hill Education.

Chapter 20, Software Testing Strategies, Section 20.1.3: The text emphasizes that a realistic view of testing acknowledges that exhaustive testing is impossible. It states, "the tester should prioritize tests that have the highest likelihood of uncovering the most severe errors." This principle is the foundation of risk-based prioritization, which is the core of the correct answer.

3. University of Texas at Austin, Department of Electrical and Computer Engineering. EE382V: Software Testing Course Notes, Lecture 5: Test Selection, Minimization and Prioritization.

Section on Test Case Prioritization: These course materials discuss techniques for ordering test cases when resources are limited. Risk-based prioritization is presented as a key industry practice. The notes explain that test cases targeting higher-risk functionalities are scheduled for earlier execution to provide the most critical feedback as quickly as possible, which is precisely the situation described in the question.