7. (Advantages of std::enable_if)

Which of the following statements can be considered useful features of std::enable_if?:

a) More user-friendly error messages than when using ‘raw’ (unrestricted) template parameters.

b) Its use can lead to more robust code.

c) It restricts templates to types that have certain properties.

d) Its use reduces the amount of boilerplate code that needs to be written.