Most "rock" guitarists find it easier to play in a minor key. The least complicated minor key is the "Relative Minor". This is just the sixth not in a scale. In the case of C Major (C D E F G A B) the sixth note is "A". This means you could solo through the whole passage in A Pentatonic, even the Dm chord.
You could also solo using C Major through the whoel progression. This is because all the chords are in the key of C.
I don't know how familar you are with modes, so I'll avoid using those as examples. There are other scales you can use which are in the key of C, but to avoid confuession too soon, I won't mention them. If you're interested in learning about modes then there are plenty of good sites around. Start here, there's some useful lessons. Then I suggest looking where I initially learnt a lot of stuff from. Ultimate Guitar Page - there's a link from GT.
Sorry if I've not helped any, hopefully you understand what I meant. If not, feel free to ask any question. If you want some help with modes too feel free to ask - it's what these forums are for!!!! Good luck and have fun.