Which of the following statements are correct?

A. The Theravada was propagated in Ceylon by Ashoka's son Mahendra.

B. The most important branch of the Theravada was the Sarvastivada, founded by Rahulabhadra.

C. Paramartha was the founder of Mahasanghika sect.

D. The Purvasailas, Aparasailas, Uttarasailas and Chaityakas are the sects that branched off from the Mahasanghikas.

E. For the first time we find directions for erecting stupas and Chaityas in the text Nidan Katha.

Choose the correct answer from the options given below :