Well I think C is the most powerful language Due to the following reasons!
1) AT first C , It's a systems language (which means it can be used to do low-level programming with minimal or no run-time).
2) Speed of the resulting application. C source code can be optimized much more than higher-level languages because the language set is relatively small and very efficient. It is about as close as you can get to programming in assembly language, without programming in assembly language. and you can even use assembly and C together!
3) C has which is its application in Firmware programming (hardware). That is due to its ability to use/work with assembly and communicate directly with controllers, processors and other devices.
4) C is a building block for many other currently known languages. Look up the history of C and you will find that it has been around for some time (as programming languages go anyway). Take a look at Python for example a fully Object-Oriented High-Level programming language. It is written in C (perhaps C++ too). That tells you if you ever want to know what is going on under the hood in other languages; understanding C and how it works is essential.
An applications language is used for high-level programming, e.g. writing a word processor or game. Examples of applications languages are Java, C#. The reason is because they contain garbage collection, automatic typing, run-time validation, etc. - where the focus is productivity.
A systems language is used for low-level programming. e.g. A micro-controller, a driver, and OS kernel. Examples include assembly, C. They require little or no runtime to run code directly on the hardware, and the focus is for the programmer to have direct control over the hardware.
Overall, it's declining as an applications language, but still holding strong as a systems language.