To answer this question, we need to understand the historical context of Madhya Pradesh.
Madhya Pradesh was a part of the Central Provinces and Berar, which was a province of British India. The capital of the Central Provinces and Berar was Nagpur.
In 1950, the Indian states were reorganized on linguistic lines, and Madhya Pradesh was formed by merging the Central Provinces and Berar with several other princely states. Initially, Nagpur was chosen as the capital of Madhya Pradesh.
However, in 1956, there was a further reorganization of states in India, known as the States Reorganization Act. As a result, Nagpur was no longer the capital of Madhya Pradesh and it was shifted to Bhopal.
Therefore, the correct answer is option B) Nagpur, as it was the capital of Madhya Pradesh till 1956.