Could not obtain a C# compiler. C# compiler not found for Mono / .Net 4.0

Tried to build a monodevelop project in Linux Mint 17.3 but got the following error message

Could not obtain a C# compiler. C# compiler not found for Mono / .Net 4.0

To fix this do:

$: sudo apt-get install mono-gmcs

Reference(s):
http://stackoverflow.com/questions/8022653/c-sharp-compiler-not-found-when-building-a-package-monodevelop-linux