Final answer:
PERT and Decision trees are commonly used to review activity and project risk, with Decision trees enabling choice assessment and PERT dealing with task scheduling and risk consideration.
Step-by-step explanation:
To answer your question, out of the options provided, Decision trees and PERT (Program Evaluation and Review Technique) are commonly used to review activity and project risk. Decision trees help in making informed choices between several courses of action, considering the probabilities and costs of possible outcomes, which directly deals with project risk management. On the other hand, PERT is a project management tool used to schedule, organize, and coordinate tasks within a project and it includes the consideration of risks and uncertainties which affect the project timeline. S-curves are also associated with reviewing project performance but are not as specifically tuned to risk analysis. Net Present Value (NPV) is an economic analysis tool and does not specifically address project risk, but it can play a role in the financial assessment of a project's potential risks and outcomes. Therefore, in the context of direct risk assessment and project review, PERT and decision trees are more appropriate tools.