Einstein Proposed Two Basic Principles or Laws as the Foundation

Multiple Choice

Einstein proposed two basic principles or laws as the foundation of his special theory of relativity. One of these principles is intuitively plausible, while the other seems quite implausible or odd to our intuitions. The principle that is intuitively plausible is

A) the principle of the constancy of lightspeed.
B) E=mc².
C) the principle of relativity.
D) the principle of time dilation.
E) the principle of inertia.