Watch the Bell Bottoms online guitar lesson by Jeff McErlain from Soloing the Changes
Cmaj pentatonic basically works here, but not really. I've heard many people fumble through this one and miss the mark. With all due respect, Mr. Clapton on his recording missed a few opportunities. If you hear him play on the song since, he clearly spent some time on the changes and kills it now.
To be clear, Clapton is one of my favorite players, if you're one of the people who thinks he's overrated, I will kindly say go back and listen to his catalog! Especially the early stuff.