How set value if there is no data in another table?

Question

ill try to locate if my data is existing to other table and get the value of it. the problem is if there is no match in the other table i got an error but there's a match the controller save the value in my database. this is my code

 

and i got this error: Object reference not set to an instance of an object. if the "ReceiverCityId" has no value in "Location " i got an error. plsss help i need to set value into 0 if the "ReceiverCityId" has no value in "Location " 

var rate = _rateService.GetRatebyParentId(Convert.ToInt32(pickup.Client.ParentClientId ?? 0));
var transaction = new Transaction
{
   Source = "Pickup",
   TransactionId = pickup.Id,
   Amount = (rate != null ? rate.RateItems.FirstOrDefault(x => x.Location ==
   _cityService.Get(pickup.ReceiverCityId).Name).Amount : 0) - 10,
   DateCreated = DateTime.Now,
   CreatedBy = User.Identity.Name,
   ReferenceNumber = pickup.ReferenceNumber
};
_transactionService.Add(transaction);