ANS:D - both (b) and (c).

An ideal material for making cooking vessels should have both (a) high heat capacity and (c) high thermal conductivity. Explanation:

1. High heat capacity: A material with high heat capacity can absorb and retain a significant amount of heat energy. This property allows the material to distribute heat evenly throughout the cooking vessel, preventing hot spots and ensuring uniform cooking. Additionally, high heat capacity helps the cooking vessel maintain its temperature even when food is added, ensuring consistent cooking performance.
2. High thermal conductivity: High thermal conductivity means that the material can efficiently transfer heat from the heat source to the food being cooked. This property ensures rapid and uniform heating of the cooking vessel, reducing cooking times and improving energy efficiency. Foods cook more evenly and quickly when the cooking vessel has high thermal conductivity.

By possessing both high heat capacity and high thermal conductivity, an ideal material for making cooking vessels can effectively absorb, distribute, and transfer heat, resulting in efficient and consistent cooking performance. Therefore, an ideal material for making cooking vessels should have both (a) high heat capacity and (c) high thermal conductivity.