The average kinetic energy of a particle in SHM is given by:
\[
K_{{avg}} = \frac{1}{2} m \omega^2 a^2
\]
where \( \omega = 2 \pi v \) is the angular frequency. Substituting the expression for \( \omega \), the average kinetic energy becomes:
\[
K_{{avg}} = \pi^2 ma^2 v^2
\]
Hence, the correct answer is (d).