Final answer:
The spiritual father of all Sikhs (Khalsas) is Guru Gobind Singh, the tenth Sikh Guru, who founded the Khalsa order and is recognized for his influential role in shaping Sikh history and identity.
Step-by-step explanation:
The spiritual father of all Sikhs, also known as Khalsas, is Guru Gobind Singh. He was the tenth Sikh Guru and is often honored for his significant contributions to Sikhism, including the founding of the Khalsa order in 1699. Guru Gobind Singh holds a special place in Sikh history as he introduced important Sikh rites of initiation and fought for the community's rights and identity. While Guru Nanak Dev Ji is the founder of Sikhism and obviously plays a critical role as the first Guru, it is Guru Gobind Singh who is regarded as the father of the Khalsas. Therefore, the correct answer to the question of who is the spiritual father of all Sikhs (Khalsas) is A) Guru Gobind Singh.