Why do computers seem so smart today, according to this book?

Question $23$ options:

A$)$

Computers are actually smarter than humans.

B$)$

Developers program many algorithms and can share one another's code.

C$)$

Computers are programmed to learn from users, a process known as "artificial intelligence" $($AI$.)$

D$)$

All of the above

E$)$

B and C only