Explanation:

Taking advantage of the growing weakness of the central authority, two men of exceptional ability,MurshidQuli Khan and Alivardi Khan, made Bengal virtually independent. Even though MurshidQuliKhan was made Governor of Bengal as late as 1717, he had been its effective ruler since 1700, when hewas appointed its Dewan.

The founder of the autonomous kingdom of Avadh was Saadat Khan who was appointed Governor ofAvadh in 1722. He was an extremely bold, energetic, iron-willed, and intelligent person.

Haidar Ali gradually rose in the Mysore army. He soon recognised the advantages of western militarytraining and applied it to the troops under his own command. He established a modern arsenal in Dindigulin 1755 with the help of French experts In 1761 he overthrew Nanjaraj and established his authorityover the Mysore state.

Shahu, grandson of Shivaji, had been a prisoner in the hands of Aurangzeb since 1689. Shahu wasreleased in 1707 after Aurangeeb's death. Very soon a civil war broke out between Shahu at Satara and hisaunt Tara Bai at Kolhapur. Arising out of the conflict between Shahu and his rival at Kolhapur, a newsystem of Maratha government was evolved under the leadership of BalajiVishwanath, the Peshwaof King Shahu.

Hence, pairs 2 and 4 are correctly matched.