Which of the following is an example of a restrictive trade practice…

The correct answer is Option (1) → Two cement makers in a region agree to raise their prices together, though their costs have not gone up.

Option (1) Two cement makers in a region agree to raise their prices together, though their costs have not gone up. — Correct. A restrictive trade practice manipulates price or the flow of supplies, so that an unjustified cost falls on the consumer. Raising prices together, when costs have not gone up, does this.

Option (2) A soap maker claims that its soap contains sandal oil, though it contains none. — Incorrect. Falsely representing the composition of goods to sell them is an unfair trade practice.

Option (3) A new geyser stops heating water within a week of its purchase. — Incorrect. A fault in the manner of performance of goods is a defect.

Option (4) A courier company delivers a parcel ten days later than the promised date. — Incorrect. A shortcoming in the manner of performance of a service is a deficiency.

An unfair trade practice misleads the buyer about the goods or service. A restrictive trade practice works through price or supply and puts an unjustified cost on the buyer.