The correct option is A (a) → (q, s); (b) → (r); (c) → (p, r)
Perhydrol is a solution of hydrogen peroxide H2O2 at a concentration
of 30% of weight by volume(w/v) or 100 volume strength. It is used as a rocket propellant.
Strictly speaking, sodium hexametaphosphate is a hexamer of composition (NaPO3)6.
It is sold by the name Calgon - S and is used in water treatment to treat/soften permanently hard water.
The actual composition of Calgon is a mixture of polymeric metaphosphates, only one of which is the above hexamer.
It is more correctly termed sodium polymetaphosphate.
Zeolite is particularly effective in removing/treating permanent hardness of water.