Scarcity refers to the limited availability of resources in relation to unlimited wants and needs. It is a fundamental concept in economics and has various manifestations in our daily lives. The options provided are examples of scarcity, except for option D, which is not a manifestation of scarcity.

Explanation:

1. Long queues at railway booking counters: This is a manifestation of scarcity as it indicates a high demand for railway tickets compared to the limited number of available tickets. The scarcity of tickets leads to long queues as people compete for the limited resources.

2. Crowded buses: This is also a manifestation of scarcity. It implies that there is a higher demand for bus transportation compared to the available seating capacity. The limited number of seats on buses leads to overcrowding and people having to wait for the next available bus.

3. Shortage of essential commodities: This is another clear example of scarcity. When there is a shortage of essential commodities such as food, water, or fuel, it means that the demand for these resources exceeds the available supply. People may have to face difficulties in obtaining these commodities due to their limited availability.

4. Sunlight: Unlike the other options, sunlight is not a manifestation of scarcity. Sunlight is a natural resource that is available abundantly and is not limited by human intervention. While sunlight may have various implications for activities such as agriculture or energy production, its availability is not constrained by scarcity.

In summary, scarcity is a concept that arises when resources are limited in relation to unlimited wants and needs. Long queues at railway booking counters, crowded buses, and shortages of essential commodities are all manifestations of scarcity. However, sunlight, being a natural resource that is abundant and not limited by human intervention, is not a manifestation of scarcity.