Is C language case sensitive

adjective. If a written word such as a password is case-sensitive, it must be written in a particular form, for example using all capital letters or all small letters, in order for the computer to recognize it . [computing]

Yes, python is a case-sensitive language without a doubt . If we write a variable in a small letter and want to use it further in the program, then use it in the same manner only otherwise it will be considered as you are using a new variable.

Kotlin language spec claims identifiers are case-sensitive yet the following produces compiler error messages because of apparently case-insensitive generated getters/setters.