The Head Officer of the state treasury during reign of Chandra Gupta Maurya was known as

The correct answer is (a) Samaharta.

The Samaharta was the head officer of the state treasury during the reign of Chandra Gupta Maurya. He was responsible for collecting taxes, managing the royal household, and overseeing the construction of public works. The Samaharta was a powerful and important figure in the Mauryan government.

The other options are incorrect.

(b) Karmantik was the head of the royal mint.
(c) Sannidhata was the head of the royal library.
(d) Douwarik was the head of the royal bodyguard.