Graduate Pharmacy Aptitude Test (GPAT) 2011 Solved Paper

Magnesium trisilicate is considered to be a better antacid than aluminium hydroxide due to its following additional properties:
[P] It has a fixed chemical composition
[Q] It forms colloidal silicone dioxide
[R] Magnesium ions overcome constipation
[S] Magnesium ions cause higher inhibition of pepsin than aluminium ions Choose the correct combination of statements