In solution, detergent dissociates as—

• a$\mathrm{C_{12}H_{25}SO_4^-}$ and $\mathrm{Na^+}$
• b$\mathrm{C_{12}H_{25}^+}$ and $\mathrm{SO_4Na^-}$
• c$\mathrm{C_{17}H_{35}COO^-}$ and $$
• d$\mathrm{C_{12}H_{25}OH}$ and $\mathrm{Na^+}$