Futures and options 3

So future and option is a zero sum game. The person who has bought the call option has not sold so the person who has sold the call option would not have received this option back so the final settlement credit or debit it is done by/to the final remaining seller.

whenever a trader enters a futures or option agreement, he/she has to pay the margin amount
therefore the trader cannot default the position
to buy call option you just have to pay the premium