Why C is more popular than C++?

because C is mainly used in all embedded systems "97%" but C++ is a desk top application which has more comparable packages that can be used instead

C with OOP is nothing but C++, basically extension of C with Object Oriented programming concepts. 

For C++ development, one should have the good knowledge of C language as it is the basis for C++, so C is popular.

One best reason is that C is preferred first to understand the C++, in order to learn programming language C is best for beginners.... because C gives a way of understanding the logic and understanding of programming...