Explanation:

• By the second decade of the 18th century the Maratha powers under Peshwa Baji Rao I were striking out against the Mughals in the Deccan and in central India.
• In 1719 Balaji Vishwanath returned from Delhi with firmans for Chauth and Sardeshmukhi. The Maratha king became the Sardeshmukh of the entire Deccan (Aurangabad, Berar, Bidar, Bijapur, Hyderabad, and Khandesh) and Karnataka.
• Originally the Peshwa was only a mukhyapradhan or prime minister and his post was not hereditary.
• When Baji Rao, Balaji Vishwanath's son, became Peshwa in 1720, the office became hereditary. In 1740 Balaji Baji Ra'o (Nana Saheb) became Peshwa. Hence option (b) is the correct answer.
• Till Shahu's death in 1749, he was still under the restraint of the Raja of Satra. Thereafter, he virtually dislodged the Raja from sovereign power.