trigger checkboxupdate on Opportunity (Before insert, before Update)  
{if(trigger.isInsert)    
   {for(Opportunity acc:trigger.new)    
        {acc.IsPrivate=True;}
 }}

Whats the code to execute in Anonymous window.? I get error in below Excution. Please suggest

Opportunity acc = new Opportunity(String Name='TrigOrangesCTRL', Date CloseDate='12/17/2017', String StageName='Prospecting');
insert acc;

What is the use of Scope Parameter in Batch Apex?

I do not understand how to fix this. This message came up while I was trying to do a challenge in Trailhead "The 'Account Manager' contact role for 'Washington Industries' could not be found or it is not set to the current user."