Step 1: Understand the properties of Balsa wood.
- Balsa wood is lightweight and has a low density, making it ideal for flight dynamics. Any alternative material must have similar characteristics.
Step 2: Analyze the given options.
- Rattan cane: Relatively dense, not suitable. Incorrect.
- Jute plant stem: Lightweight and low density, suitable as an alternative. Correct.
- Pine wood: Denser than jute, not suitable. Incorrect.
- Mango wood: Very dense, unsuitable for the glider. Incorrect.
Step 3: Conclude the answer.
The most suitable material is:\[
{\text{B - Jute plant stem}}.
\]