Concept:
Bio-aesthetic planning means using plants and natural beauty for improving the environment and appearance of human settlements.
Step 1: Understand bio-aesthetic concept.
Bio-aesthetic concept is not limited to a small garden. It is related to planned use of vegetation for beauty, health and environmental improvement.
\[
\text{Bio-aesthetic planning} \Rightarrow \text{beautification with plants}
\]
Step 2: Apply to landscape gardening.
In town planning, roads, parks, residential areas and public spaces are designed with plants and landscape elements.
\[
\text{Town planning} \rightarrow \text{large-scale landscape planning}
\]
Step 3: Compare with other options.
Gardens, parks and rooftops are parts of landscaping, but the broadest and most essential application of bio-aesthetic concept is in town planning.
\[
\therefore \text{Correct Answer is (B)}
\]