5. (2004 Fujian Province High School Mathematics League Preliminary) The 4 faces of a regular tetrahedron are labeled with $1,2,3,4$. Four such uniform regular tetrahedrons are simultaneously thrown onto a table, and the product of the 4 numbers on the 4 faces that touch the table is divisible by 4. The probability of this happening is
A. $\frac{1}{8}$
B. $\frac{9}{64}$
C. $\frac{1}{16}$
D. $\frac{13}{16}$
5. D The case where the product of 4 numbers is not divisible by 4 is when 4 does not appear, and 2 appears at most once, with a probability of $\left(\frac{1}{2}\right)^{4}+4 \times \frac{1}{4} \times$ $\left(\frac{1}{2}\right)^{3}=\frac{3}{16}$, so the probability that the product of 4 numbers is divisible by 4 is $\frac{13}{16}$.
6. D $\quad P=\frac{3}{10} \times \frac{2}{9} \times \frac{7}{8}=\frac{7}{120}$