Question: What is the correct query to find all of the people who have a home phone number defined?

1. `db.person.find({exists: 'homePhone'});`
2. `db.person.exists({homePhone: true});`
3. `db.person.find({homePhone: {$exists: true}});`
4. `db.person.has('homePhone');`

Answer: The correct answer of the above question is Option C:`db.person.find({homePhone: {$exists: true}});`