I find it hard to pinpoint who THE inventor was of C, or Unix for that matter. Every tech evolution has been influenced by other tech evolutions, and between where one thing stops and the next thing starts is often an arbitrary line, just as those things themselves are conceptually arbitrary as well. At the same time we can not deny that there is variation and difference in the world around us and we can easily see how defining 'things' is useful, unavoidable, necessary.
What is clear is that we are talking about a group of very creative, productive, computer scientists: Kenneth Thompson, Dennis Ritchie and Brian Kernighan, all employees of one Bell Labs department, who, at a certain moment in time, in the beginning of the seventies, got the opportunity to work together really well on the remnants of a project that had been abandoned by the mother firm.
Together they started working intensively on the computers PDP-7 and PDP-11, creating an operation system and utilities for it. Unix and C were the result of this process. Unix later produced Linux, and C produced nearly all the modern programming languages we know today.
The importance of these developments for contemporary computing can hardly be overstated.