Explanation:

Statement 2: The Indus valley people knew the use of copper, bronze, silver, gold but not iron. So, 2 is wrong.
Statement 1: The Ramayana mentions chariots covered with leather. The Rig Vedic charioteers used varma (coats of mail) and sipra/sironastra (helmets).
Equipped with asi (swords), hanas (arrows) and ilhianus (bows), the Kshatriyas on the chariots went to combat.
Since statement 2 is wrong, given the options 1 must be correct.
Statement 3: This is a disputed Statement.
The Rig Veda mentions horse-drawn chariots with spoked wheels.
But there is very little archaeological evidence of horses during the Harappan era and none at all earlier. The existence of the Harappan horse is a hotly disputed topic among archaeologists.
Arguments:
? Some claim that horse was NOT known.
? Among the numerous seals found in Harappa there is none which represent a horse, while other animals like the bull, buffalo, and goat are represented.
? Moreover, the cavalry (of horses) as an organised force can be traced only to the post vedic period, but not earlier.
Arguments against:
On the other hand, some scholars claim that the horse was widely domesticated and used in India in the area covered by the Indus-Sarasvati (or Harappan) Civilisation, but this evidence remains unsubstantiated.
FINAL VIEW: But, based on the above, to say that “there is no evidence of Indus Valley people having been aware of this animal” is WRONG because there is no conclusive evidence that tells us whether they knew about horses, or whether they were aware of horses. We have insufficient evidence to claim anything about the connection between horses and Indus valley.
Statement 3 is thus incorrect.