In the Next Two Months Some New Features Will Be

In the next two months some new features will be constantly added to new releases of a project you are working on as Test Manager. You have identified as one of the main project risks, that the requirements specification will still be incomplete when your team starts the test design and implementation phase. Some requirements will most likely be completed too late to allow a proper test preparation. You and your test team have already worked on several similar past projects in the same organization. Which one of the following options would you expect to be the most effective at mitigating this risk?

A) Don't prepare any test and just run the regression test suite to check that the new features don't introduce regression.
B) Make reasonable assumptions about the missing details and design lightweight tests that can be easily updated during test execution.
C) Don't design any test until the test execution starts, then communicate that test execution is blocked due to incomplete requirements.
D) Even if there are only few details missing, escalate the risk to the project manager without preparing any tests.