Business Law (Law Contract) - an ad in a newspaper

This is my 1st module which is business law. I'm having a hard time understanding my lectures and I really need help on my assignment;

"John, a retired businessman, placed an advertisement in the newspapers to sell his house for $3million. The next day, Adam comes to view the property and told John he would like to buy the house for $2.2million. John says nothing. A short while later Bill comes to view the property and agrees to John's price of $3million but "subject to contract". John agrees to this. In the evening of the same day, Charles comes to view the house and immediately insisted on purchasing it. He tells John he is prepared to pay $3.2million for the house; $200,000 more than the original price. John agrees and the next day, John and Charles go to a conveyance lawyer to complete the contract of sale. Adam and Bill come to hear of this and are now considering legal action against John.

Advise Adam and Bill on the possibility of them taking up legal action against John."

Really appreciate some kind souls to help me with this! :)

My apologies that I didn't state. Its the suggestion towards the assignment of how we can advise Adam and Bill on the possibility to take up legal action. :) Thank you so much for your time and guidance!

1- Adam and Bill have different situations. This is a law question, so you must write one paragraph for each situation using IRAC (issue, rule, application, and conclusion). Google IRAC.

2- Adam: I don't think Adam has an action because John never accepted the offer.

3- Bill: Even though John accepted the offer, the contract was not perfected because it was "subject to contract."

I could be wrong. Take my advice with caution. I don't know what is the law in your country.

My two cents.