Final answer:
After Nadir Shah's assassination, Ahmad Shah Durrani became his immediate successor and established the modern state of Afghanistan in 1747. Mohammed Zahir Shah ascended the throne much later, in 1933. The correct option is b.
Step-by-step explanation:
Following the assassination of Nadir Shah in 1747, it was Mohammed Zahir Shah who ascended the throne of Afghanistan. Mohammed Zahir Shah was not immediately after Nadir Shah but came into power years later.
The immediate successor of Nadir Shah, the founder of the Afghan Empire, was Ahmad Shah Durrani, also known as Ahmad Shah Abdali.
Ahmad Shah Durrani is considered the founder of the modern state of Afghanistan, establishing it in 1747, reinforcing and unifying the various tribes.
However, Mohammed Zahir Shah became king of Afghanistan much later, in 1933, following the abdication of his father, King Nadir Shah, who had been in power for only one year before his assassination. The correct option is b.