Which event spread Islam to India. Please help

The history of the spread of Islam spans about 1,410 years. Muslim conquests following Muhammad's death led to the creation of the caliphates, occupying a vast geographical area; conversion to Islam was boosted by missionary activities, particularly those of imams, who intermingled with local populations to propagate the religious teachings.[1] These early caliphates, coupled with Muslim economics and trading, the Islamic Golden Age, and the Age of the Islamic Gunpowders, resulted in Islam's spread outwards from Mecca towards the Indian, Atlantic, and Pacific Oceans and the creation of the Muslim world. Trade played an important role in the spread of Islam in several parts of the world, especially Indian traders in southeast Asia.[2][3]

Muslim dynasties were soon established and subsequent empires such as those of the Umayyads, Abbasids, Fatimids, Mamluks, Seljukids, and the Ayyubids were among some of the largest and most powerful in the world. The Ajuran and Adal Sultanates, and the wealthy Mali Empire, in North Africa, the Delhi, Deccan, and Bengal Sultanates, and Mughal and Durrani Empires, and Kingdom of Mysore and Nizam of Hyderabad in the Indian subcontinent, the Ghaznavids, Ghurids, Samanids, Timurids, and Safavids in Persia, and the Ottoman Empire in Anatolia significantly changed the course of history. The people of the Islamic world created numerous sophisticated centers of culture and science with far-reaching mercantile networks, travelers, scientists, hunters, mathematicians, physicians, and philosophers, all contributing to the Islamic Golden Age. The Timurid Renaissance and the Islamic expansion in South and East Asia fostered cosmopolitan and eclectic Muslim cultures in the Indian subcontinent, Malaysia, Indonesia and China.[4]

The correct answer is b