...................acts like a bank and keeps securities in electronic form on behalf of the investor.

Depository

The correct answer is option 2- Depository.

Depository acts like a bank and keeps securities in electronic form on behalf of the investor.

Just like a bank keeps money in safe custody for customers, a depository also is like a bank and keeps securities in electronic form on behalf of the investor. In the depository a securities account can be opened, all shares can be deposited, they can be withdrawn/ sold at any time and instruction to deliver or receive shares on behalf of the investor can be given.