4. Roll a die twice, record the number of dots each time, and multiply these numbers. The probability that the product is 2 is ( ).
A. $\frac{1}{36}$
B. $\frac{1}{18}$
C. $\frac{1}{9}$
D. $\frac{2}{9}$
E. $\frac{1}{6}$
B

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