Yajurveda - “Yajus” means “sacrificial formula” and Yajurveda is the book of sacrificial prayers.
It compiles ritual-offering Mantras/chants.
It has two types – Krishna (Black) & Shukla (White)
The term Krishna-ayas, Shyama, and Shyama-ayas as in the Yajur Veda and Atharva Veda are believed to be the early names of iron. Hence, option 3 is correct.
Rigveda- It is the oldest veda (1800 – 1100 BCE).
It has 1028 hymns called ‘Suktas’ and is a collection of 10 books called 'Mandalas'.
Samaveda- it is Known as the Veda of melodies and chants.
It is dated to 1200-800 BCE.
This Veda is related to Public Worship.
Vinaya Pitaka- it is one of the three Pitaka of Buddhism.
It consists of rules of conduct and discipline applicable to the monastic life of the monks and nuns.