in question No 4 he was asking not about Feroz Tughlaq , but the Rulers before him e.g Mohammed bin Tughlaq and Alauddin Khilji. 'the reign of feroz tuhglaq CLOSED the most brilliant epoch of muslim rule" comment.

I interpretd it as he enthroned in 1451 so the start of his reign closed the period Mohammed bin Tughlaq (1426-1451). So, the examiner wanted to ask about Mohammed bin Tughlaq.