Arrange the following sets in increasing order, on the basis of their cardinality :
A. $A_1 = {{1,2},{3}}$
B. $A_2 = {{1},{2},{3},{4}}$
C. $A_3 = {{1,2,3,4,5,6}}$
D. $A_4 = {{1,2},{2,3,4},{5}}$
E. $A_5 = {{1},{2},{3},{4},{5}}$
Choose the correct answer from the options given below :