Answer:
(A) De Beers and (C) more price elastic
Step-by-step explanation:
De Beers deals in diamonds which are luxury goods while local water utility provides an essential good i.e water.
If both raise their prices, water being a necessity, it's demand would be inelastic i.e won't be affected, while diamond is a luxurious good with more price elastic demand.
Price elasticity of demand refers to degree of responsiveness of quantity demanded with change in price.
To conclude, De Beers is more likely to see it's total revenue fall in comparison to local water utility.