gistfile1.txt

public class WeekTwoHomework {

// method (a)
    public static void showAccNames(){
        integer i=0;
        for (Contact c : [SELECT Id, Account.Name, Account.Industry FROM Contact]){
            i++;
            System.debug ('Name of Account # ' + i + ' is ' + c.Account.Name);
        }             
    }

// method (b)
     public static void showContNames(){
         for(Account a : [SELECT Id, Name, (SELECT Name FROM Opportunities WHERE StageName = 'Closed Won') FROM Account]){
             List<Opportunity> oppsList = a.opportunities;
              	for (Opportunity opp : oppsList){
                    System.debug('Name of Opportunity for account' + a.Name + ' is ' + opp.Name );
             }
         }
     }   

// method (c)
   public static Map<Id, Opportunity> returnOppMap(){
        return new Map <Id, Opportunity>([SELECT Id From Opportunity]);
        }

// method (d)
    public static integer showNumOpenOpps(){
        return [SELECT COUNT() FROM Opportunity WHERE isClosed = false];
    }
}

Wow awesome job @niavesper !! 🥇 I love that you've used SOQL For loops and also having return types on your methods are awesome.