So we need to add the basis onto the value of the option. These four factors contribute to the time value of the option. The time value is a combination of the time to expiry, volatility of the underlying asset and basis which includes dividend stream. But that s not all because we have had to pay something for this option. That means that we need to discount the value of the option because we could have put the money we paid for it in the bank and earned interest on it.
Options have various properties that are quantified using Greek symbols.
Delta this is the change in option price relative to change in the price of the underlying asset. The delta of a put option can be between 0 and 1. E.g. a call option is valued at 20p and has a delta of 0.2. The underlying asset goes up by 1p so the call option is now worth 20.2p. The delta of an option is not constant.