Which two statements enable the developer to save the records to the database without an Id?

A developer needs to save a List of existing Account records named myAccounts to the database, but the records do not contain Salesforce Id values. Only the value of a custom text field configured as an External ID with an API name of Foreign_Key__c is known.

Which two statements enable the developer to save the records to the database without an Id? (Choose two.)
A . Upsert myAccounts Foreign_Key__c;
B . Upsert myAccounts(Foreign_Key__c);
C . Database.upsert (myAccounts, Foreign_Key__c);
D . Database.upsert(myAccounts).Foreign_Key__c;

Answer: A,C