The unary scope resolution operator is used:

a. To access a global variable when a local variable of the same name is in scope.
b. To access any variable in an outer block when a local variable of the same name is in scope.
c. To access a global variable when it is out of scope.
d. To access a local variable with the same name as a global variable.

a. To access a global variable when a local variable of the same name is in scope.