organic chemistry - Which proton in cyclohexene is the most acidic?

I know that $\mathrm{H^b}$ is most acidic due to conjugation (resonance).

But I am confused as to how to compare $\mathrm{H^a}$ and $\mathrm{H^c}$. I think $\mathrm{H^a}$ should be more acidic than $\mathrm{H^c}$ due to hyperconjugation.