Explanation:

1. Banda Bahadur was appointed as the military leader of the Sikhs by Guru Gobind Singh.
2. Guru Arjan Dev became the Sikh Guru after Guru Ram Das.
3. According to Sikh tradition, Gurmukhi (literally, “from the mouth of the Guru”) was invented in the mid-16th century by Angad, the second Sikh Guru (head of the Sikh religion), in order to correct certain inadequacies in the Lahnda script so that sacred literature might be accurately recorded. However, the script is known to have existed before Angad’s time, and he is now considered the popularizer or standardizer of Gurmukhi rather than its originator.