Option 1: Connective tissue is involved in various functions such as support, protection, and binding of other tissues. It does not have a specific role in transporting hormones, heat, or maintaining water balance. Therefore, option 1 is incorrect.

Option 2: Muscular tissue is responsible for movement and generating heat. However, it does not have a role in transporting hormones or maintaining water balance. Therefore, option 2 is incorrect.

Option 3: Blood is the correct answer. It functions as a transport medium in the body and carries hormones from endocrine glands to target organs. It also helps in heat distribution throughout the body. Additionally, blood helps to maintain water balance through its components, including plasma, red blood cells, and electrolytes. Therefore, option 3 is correct.

Option 4: Nervous tissue is involved in transmitting electrical signals in the body. It does not have a role in transporting hormones, heat, or maintaining water balance. Therefore, option 4 is incorrect.

In conclusion, the correct answer is option 3, blood, as it transports hormones, heat, and maintains water balance in the body.