Dr. Rajendra Prasad was a great leader.

Explanation:

• Sweet: This adjective typically describes taste or personality traits that are kind and pleasant. While Dr. Rajendra Prasad may have had positive personality traits, "great" is a more suitable adjective to describe his stature as a leader.
• Lovely: This adjective implies beauty or charm, which may not fully capture the qualities and significance of Dr. Rajendra Prasad's leadership.
• Big: While "big" could refer to influence or impact, it is not as strong and specific as "great" in describing someone's leadership qualities.
• Great: This adjective is commonly used to describe leaders who have had a significant impact, influence, and importance in their field. It's the most appropriate choice to describe Dr. Rajendra Prasad's leadership role.