The amplitude of vibration of a particle is given by ${\mathrm{a}}_{\mathrm{M}}=\frac{\left({\mathrm{a}}_0\right)}{\left({\mathrm{a\omega }}^2-\mathrm{b\omega }+\mathrm{c}\right)}$ where a₀ , a, b and c are positive. The condition for a single resonant frequency is

• A

  b² = 4ac

• B

  b² > 4ac

• C

  b² = 5ac

• D

  b² = 7ac