Engineering Properties of Grains

The sphericity $\Phi$ of an agricultural grain having three mutually perpendicular dimensions $a$ (major), $b$ (intermediate), and $c$ (minor) is defined as:

Options:

• (A) $\Phi = \frac{(a b c)^{1/3}}{a}$
• (B) $\Phi = \frac{a + b + c}{3 a}$
• (C) $\Phi = \frac{a b c}{a^3}$
• (D) $\Phi = \frac{\sqrt{a b c}}{a}$