Stephen Hawking was a theoretical physicist known for his work on black holes and cosmology. He was the Lucasian Professor of Mathematics at the University of Cambridge between 1979 and 2009.
(a) Computer Science is the study of computers and computational systems. It is a broad field that encompasses a wide range of topics, including computer hardware, software, and artificial intelligence.
(b) Organic Chemistry is the study of the structure, properties, and reactions of organic compounds. Organic compounds are compounds that contain carbon, and they are the basis of all living things.
(c) Plant Pathology is the study of diseases that affect plants. Plant diseases can be caused by a variety of factors, including viruses, bacteria, fungi, and insects.
(d) Theoretical Physics is the study of the fundamental laws of nature. Theoretical physicists use mathematics and logic to develop theories that explain the behavior of matter and energy.
The correct answer is (d).