I am not sure about C.
I have done a lot of programming with it, and in the future it also seems like I will do more with it, but sometimes I bang my head on my table and against my wall because my malloc sets a struct and a string to the same memory position (I still remember it: 0x6010111) and I can't find out why and then I wish I had done it in lua.

I would say C is good if you want to write a small, self-contained command line-utility, like cat, or a programming language. These are tested often, speed is crucial, and it is _very_ portable.

Things I wouldn't use C for is developing something security critical. Seriously, we have to ban this. Heartbleed was one example, and there is so much more that we don't know-this should be stopped. seriously.