Who became the Nawab of Bengal after Alivardi Khan?

Siraj-ud-Daulah

The correct answer is Option 3- Siraj-ud-Daulah.

Alivardi Khan died on April 9, 1756, and was succeeded by his daughter's son, Siraj-ud-Daulah, who was aged 23 at the time. Siraj-ud-Daulah was a young and ambitious ruler who was determined to assert Bengal's independence from the British East India Company. He launched a series of attacks against the company's settlements in Bengal, culminating in the Battle of Plassey in 1757. Siraj-ud-Daulah was defeated at Plassey by the company's forces, led by Robert Clive. This marked the beginning of British rule in Bengal.

The other options are incorrect. Sarfaraaz Khan was the son of Alivardi Khan, but he was passed over for the succession in favor of Siraj-ud-Daulah. Shuj-ud-din Muhammad Khan was the son of Siraj-ud-Daulah, but he was never Nawab of Bengal. Mir Zafar was the Nawab of Bengal from 1757 to 1760, but he was a puppet ruler installed by the British.