To neutralize excess HCl in the stomach, antacid medicine usually contains—

• a$\mathrm{Mg(OH)_2}$ and $\mathrm{Al(OH)_3}$
• bNaOH and KOH
• c$\mathrm{Ca(OH)_2}$ and NaOH
• d$\mathrm{Mg(OH)_2}$ and NaOH