In Huawei FusionCompute, which one is correct about the description of "role"?

In Huawei FusionCompute, which one is correct about the description of "role"?
A . A "role" can have one or more different "operating permissions"
B. If a "user" has multiple "roles", its "operating authority" depends on the "role" with the highest priority
C. The "operation authority" of the "role" cannot be modified
D. A "user" can only have one "role"

Answer: A