Where/How to instaniate an object to handle null reference exception C#

[jkenny82]

Hey guys kind of a simple question, I'm not exactly sure where/how to initialize a new object instance so I don't get this error. I have a class object(Contact) that has another class object(ContactInfo) and sometimes the user decides not to input(instantiate) the ContactInfo object. So later when I try to do a search via Contact.ContactInfo, I get the error. Below I have the line of code where I get the error and then I have the two classes:
foreach (var Contact in Contacts)
{
if (String.Equals(Contact._contactInfo.City.ToLower(), city, StringComparison.CurrentCulture))
{
ContactsByCity.Add(Contact);
}
}

// and then the two classes:

public class Contact : Person
{
private ContactInfo info;
private ContactInfoLoader loader;
public ContactInfo _contactInfo { get; set; }

public Contact()
{ }
public Contact(ContactInfo _info)
{
info = _info;
}
public ContactInfo GetContactInfo()
{
loader = new ContactInfoLoader(this);
return loader.GatherContactInfo();
}
}
public class ContactInfo
{
public string PhoneNumber { get; set; }
public string Address { get; set; }
public string City { get; set; }
public string State { get; set;}

public ContactInfo()
{ }

}