The oldest Veda is:

The correct answer is Option (1) → Rig Veda

The Rig Veda is the oldest of the four Vedas and the oldest text of the Indo-Aryans, composed roughly between 1500 and 1000 BCE. It is a collection of 1,028 hymns (suktas) arranged in ten books (mandalas), mostly in praise of gods such as Agni, Indra and Soma. The other three Vedas were composed later, in the later Vedic period.