Which of the following is the smallest number?
(A) 1.4
(B) 1.2
(C) 2.0
(D) 1.5
(E) 2.1
When we arrange the five choices from smallest to largest, we obtain $1.2,1.4,1.5,2.0,2.1$.

Thus, 1.2 is the smallest.

ANSWER: (B)