How to access Nested JSON Data via Index, Angular JS, ng-click?

I have a List of cars assigned to a person for a particular month. If you search April you will get April data. How do I access Nested JSON data via Index?

Here's plunker

   $scope.cars = $scope.results[resultIndex].cars.map(function(car) {
          return {
        make: car.Make,
            year: car.Year
          };
        });

   $scope.showCars = function(resultIndex) {
      $scope.cars = $scope.results[resultIndex].cars;
    };