Option house is a US based brokerage firm
You can make a SWIFT payment giving the details of the Broker account, Bank, SWIFT BIC [or ABA]. The broker should be able to provide you the details.
Why would an Indian citizen need to fill up form 15CA & 15CB to wire funds from Indian saving account to Trading account based in USA ?
As per FEMA [Foreign Exchange Management Act], any transfer by individuals outside of India need the 15CA & 15CB form. The 15CA is from a CA to state that taxes have been paid on the funds being transferred. The limit is 1 million USD per year.