Which one of the following was the cause of the Battle of Plassey ?

Which one of the following was the cause of the Battle of Plassey ?

The English levied heavy duties on the goods entering Calcutta
Siraj-ud-Daulah suspected that the English favoured his rivals
The English began to fortify Calcutta
Siraj-ud-Daulah was instigated by the French
This question was previously asked in
UPSC CAPF – 2010
One of the major immediate causes for the conflict between Siraj-ud-Daulah, the Nawab of Bengal, and the British East India Company leading to the Battle of Plassey was the English fortifying their factory in Calcutta (Fort William) without the Nawab’s permission. This act was seen by the Nawab as a blatant disregard for his authority and a threat to his sovereignty. He ordered the fortifications to be demolished, which the English refused, escalating tensions.
– Causes for Plassey included the British misuse of trade privileges (farman), lack of respect for the Nawab’s authority, and competition with the French.
– The fortification of Calcutta without permission was a direct provocation that led Siraj-ud-Daulah to attack and capture Calcutta in 1756.
– The recapture of Calcutta by Clive and the subsequent conspiracy and battle at Plassey followed this event.
Other factors included the shelter given to the political fugitive Krishnadas by the English, and disputes over trade duties, but the fortification issue was a significant immediate trigger for the Nawab’s military action against Calcutta.