Which Sultan of Delhi established a ‘Translation Department’ to help both communities to understand each others’ ideas better?

The Sultan of Delhi who was very concerned about charity and alms and established a department called ‘Diwan-i-Khairat’ for it, was:

Who created the department of Diwan-i-Arz in Delhi Sultanate?

Who among the following established Delhi as the capital of Sultanate?

Who was the first Sultan of Delhi to participate in the public celebration of Holi?

Under which Sultan of Delhi, Muhammad Bin Tughlaq had worked before becoming the ruler?