Explanation:

**Tipu Sultan**, the ruler of the Kingdom of Mysore from 1782 to 1799, is credited with writing 'Fathul Mujahidin'. This military manual, written in Persian, details his military strategies, tactics, and administrative reforms, particularly focusing on his innovative use of rockets in warfare against the British. It reflects his advanced understanding of military science and his efforts to modernize the Mysore army. Option B is correct. Option A, Babur, was the founder of the Mughal Empire and wrote his autobiography, 'Baburnama' (or 'Tuzk-e Baburi'), in Chagatai Turkic. Option C, Hyder Ali, was Tipu Sultan's father and a brilliant military strategist who established the Kingdom of Mysore's power, but 'Fathul Mujahidin' is attributed to Tipu. Option D, Shah Alam II, was a Mughal emperor during the late 18th and early 19th centuries, a period of decline for the Mughal Empire, and is not known for writing 'Fathul Mujahidin'.