Explanation:

Let’s break it down:

- Arhar (Option 1) is pigeon pea. It’s a pulse crop, used for dal—not for making jaggery, khandsari, or molasses.

- Coconut (Option 2) is all about copra, oil, and water. You won’t find much sugar production from coconuts.

- Linseed (Option 3) gives us flaxseed and linseed oil. It has nothing to do with sugar products or sweeteners.

- Sugarcane (Option 4) is the main source for all three: jaggery, khandsari, and molasses. It’s grown specifically for its high sugar content, which is processed into these products.