When would you choose to use C rather than C++?

Answer 1

C prefer on machine language, like microcontroller

Answer 2

Depends on the microship. Some can can compile c++ if they can: Go for c++ otherwise you must use C. If they can only compile that. Even though c++ can also compiled by a c compiler but its hard to maintain and you can only use libarys that are also available in a c compiler like print for instance.