The sanskara (rite) that initiated a boy into the life of a student (brahmachari), with the investiture of the sacred thread, is called:

The "Upanayana" sanskara is the ceremony in which a boy was initiated into student life (brahmacharya), and given the sacred thread (yajnopavita or "janeu").

About Upanayana:

• "Upanayana" means "leading near", that is, taking the student near to the teacher (guru).
• After this ceremony, the boy went to live with his teacher, to study the Vedas and other subjects.
• The boy was taught the Gayatri mantra during the ceremony.
• According to the Dharmashastras, the ceremony was to be performed at different ages for different varnas: for example, around 8 years for Brahmanas, 11 for Kshatriyas and 12 for Vaishyas.
• It was performed for boys of the three upper varnas (Brahmana, Kshatriya and Vaishya), who were therefore called "dvija" (twice-born), as the ceremony was considered a second, spiritual birth.
• Shudras and women were generally not allowed to undergo this ceremony in later times, though some early texts suggest that women also had it in the Vedic period.

About sanskaras:

• Sanskaras are rites of passage, performed at important stages of a person's life, from before birth to death.
• Traditionally, there are 16 main sanskaras ("shodasha sanskaras").

Some important sanskaras:

• Garbhadhana: before conception.
• Jatakarma: at birth.
• Namakarana: naming ceremony.
• Annaprashana: the first feeding of solid food (rice).
• Chudakarana (Mundan): first cutting of hair.
• Upanayana: initiation into studentship.
• Samavartana: completion of studies and return home.
• Vivaha: marriage.
• Antyeshti: funeral rites.

Why not the other options?

• ✗Namakarana is the naming ceremony.
• ✗Annaprashana is the first feeding of solid food.
• ✗Samavartana marks the end of student life.