Which of the following techniques can be used for reducing the total dissolved solids (TDS) in water?

(1) Ion Exchange
(2) Distillation
(3) Carding

Both 1 and 2

The correct answer is option 3. Both 1 and 2.

Both ion exchange and distillation are techniques that can be used for reducing the total dissolved solids (TDS) in water. Ion exchange involves the exchange of ions in water with ions on a resin, while distillation involves heating water to vaporize it and then condensing the vapor back into liquid form, leaving impurities behind. "Carding" is not a relevant technique for reducing TDS in water.