Which collection type should you use?

You are developing an application that includes a class named Order. The application will store a collection of Order objects.

The collection must meet the following requirements:

• Internally store a key and a value for each collection item.

• Provide objects to iterators in ascending order based on the key.

• Ensure that item are accessible by zero-based index or by key.

You need to use a collection type that meets the requirements.

Which collection type should you use?
A . LinkedList
B . Queue
C . Array
D . HashTable
E . SortedList

Answer: E

Explanation:

SortedList<TKey, TValue> – Represents a collection of key/value pairs that are sorted by key based on the associated IComparer<T> implementation.

http://msdn.microsoft.com/en-us/library/ms132319.aspx