Who among the following established a modem armoury in Dindigal Mysore in 1755 ?

The correct answer is B) Haider Ali. In 1755, while he was building his power base around Dindigul, Haider Ali set up a modern arsenal there with French technical help and European-trained gunners and craftsmen. It was an early sign of the military modernisation that made Mysore a serious opponent of the English East India Company in the later Anglo-Mysore Wars.

Why the others are wrong:

• Nanjaraj and Devaraj were the Sarvadhikari brothers who ran the Mysore administration under the nominal ruler. They were the ministers Haider eventually displaced around 1761, and they did not set up this armoury.
• Chikka Krishnaraja Wadiyar II was the titular Wodeyar ruler from 1734 to 1766. He reigned, but real decisions lay with the ministers and later with Haider.

Core concept: the rise of Mysore under Haider Ali as a military state built on European-trained artillery and infantry. For Mains, link it to how indigenous state-building in the eighteenth century was shaped by European military technology.

Trap: aspirants pick the king's or the ministers' name because they appear in the Mysore power story. The question asks who built the arsenal, and that was Haider Ali.