Final answer:
Ahmed Shah Durrani's fourth invasion of India took place in 1761, marked by the Battle of Panipat which played a significant role in shaping the regional power dynamics. The correct option is b.
Step-by-step explanation:
The fourth invasion of India by Ahmed Shah Durrani, also known as Abdali, occurred in the year 1761. This invasion is notably marked by the historic Battle of Panipat which took place on January 14, 1761.
During this period, the Mughal Empire was declining, and regional powers like the Maratha Empire were gaining strength.
Ahmad Shah Durrani's invasion targeted both the weakened Mughal and emerging Maratha empires with the intention of expanding his Afghan kingdom into the Indian subcontinent.
The resulting conflict ultimately restrained the Maratha Empire's attempts to control all of India and highlighted the shifting power dynamics in the region. The correct option is b.