The correct options are
B Aryans settled in the Gangetic valley region during the Later Vedic Age.
D The Aryans were well versed in riding horses, something which was very uncommon during the Harappan civilisation.
The Aryans originated in Central Asia, and when they moved into India, they came to be known as Indo-Aryans. The Aryans settled in the Saptasindhu region during the Early Vedic period, and in the Gangetic valley region during the Later Vedic period. Rig Veda was the first ever written literature in ancient India. Since the Aryans came from Central Asia, they were well versed in riding and using horses for various other activities.