D.
[tex] \frac{15}{20}=\frac{5}{5} * \frac{3}{4}=\frac{3}{4}\\\\
\frac{3}{4}\\
\frac{9}{12}=\frac{3}{3}*\frac{3}{4}=\frac{3}{4}\\
\frac{12}{16} = \frac{4}{4} * \frac{3}{4}=\frac{3}{4}\\
\frac{25}{30}=\frac{5}{5}*\frac{5}{6} \\
\frac{5}{6}[/tex] is the only fraction ≠ [tex] \frac{3}{4} [/tex], so D is your answer,
