Is it legal to trade stocks in USA's stock exchanges as an Indian citizen?

@nithin came across an another brokers, they are allowing to open an cash account for US trading.

Just have this query that RBI haven’t said derivatives are banned in foreign exchange via LRS but “margins or margin calls to overseas exchanges / overseas counterparty, are not allowed under the Scheme.”

Now is it possible to only Buy call/put Options using a cash account? does that also be considered as margin calls as premium is paid upfront?

can you please clarify. thanks