Which options describe Chinese developments in mathematics?

Question

(Select all that apply.)

Prior to inventing numbers, the Chinese method of number writing used clusters of short vertical or horizontal lines for digits.
The Han Dynasty invented calculus, even though Sir Isaac Newton has been given credit in most history books.
The Chinese discovered the ratio of a circle’s circumference to its diameter, known as pi (π), centuries before the Greek Empire.
The first Chinese book about mathematics, Nine Chapters on the Mathematical Art, was composed before 200 BC.

Answer 1

Your answer is?

Answer 2

B and C?