This exercise focuses on the same concepts as the previous exercise; however, an Eb is now thrown into the bass line. Before, when the only notes in the bass line were C, F, and G, it was easier to play either major or minor on top of the bass line since the line itself established no set tonality. Now that the Eb is part of the bass line, there is more emphasis towards a minor tonality (because Eb is the minor third of C).
As always, practice the bass line alone until you feel comfortable, then add the right hand and improvise. Try using a blues scale, a minor scale, a dorian scale, or anything else you can think of. You may even want to try using a major scale; this will give you lots of room for experimentation since the major scale contains E and the bass line contains Eb. Since the Eb does not enter until the last eighth note of each bar, you can imply a major tonality through most of the measure and let the Eb in the bass serve primarily as a passing tone back to C. Play different lines on top of the bass line and see what sounds correct (to you) and what does not. Use these exercises to help you figure out how you want your music to sound.