Option 1 states that Prof. C. N. R. Rao is considered to be an international authority in solid-state and structural chemistry. This means that he is highly regarded and respected in the field of solid-state and structural chemistry at an international level. Option 2 states that he is the first Indian to reach the H-index of 100, reflecting the economy of the body of his published research work. The H-index is a metric used to measure the impact and productivity of a scientist`s published research. An H-index of 100 signifies a significant amount of highly cited papers, indicating the influence and quality of Prof. C. N. R. Rao`s research.

Both statements 1 and 2 are correct, which means option 3, "Both 1 and 2" is the correct answer. The first statement establishes Prof. C. N. R. Rao`s expertise and recognition in solid-state and structural chemistry, while the second statement highlights his achievement as the first Indian to achieve an H-index of 100. Therefore, option 3 accurately represents the information given in the question.