【单选题】

It can be inferred from the passage that theCepheid variable method of estimating galactic distances would be likely to yield experimentally flawed results in which of the following circumstances

A、If the luminosity of ordinary stars being compared with that of aCepheid star were affected by parallax.
B、If the apparent brightness of theCepheid star being studied required an unusually long period of time to vary.
C、If the gravitational interference surrounding theCepheid star being observed were more negligible than in most cases.
D、If theCepheid star being studied existed on the periphery of the universe, at an extremely large distance from the observer.
E、If theCepheid star being studied were in the same galaxy as the observer.