GAUSS8 2011 Problem 21

A collection of coins includes only pennies (1 ¢), nickels (5 ¢), dimes (10 ¢) and quarters (25 ¢). Using the coins in this collection, it is possible to create any amount of money less than one dollar (100 ¢). What is the smallest possible number of coins in the collection?

Answer Choices
A. 10
B. 7
C. 11
D. 13
E. 12