A particle executes simple harmonic motion and it is located at $x = a , b$ and $c$ at time $t _ { 0 } , 2 t _ { 0 }$ and $3 t _ { 0 }$ respectively. The frequency of the oscillation is:\\
(1) $\frac { 1 } { 2 \pi t _ { 0 } } \cos ^ { - 1 } \left( \frac { a + c } { 2 b } \right)$\\
(2) $\frac { 1 } { 2 \pi t _ { 0 } } \cos ^ { - 1 } \left( \frac { a + 2 b } { 3 c } \right)$\\
(3) $\frac { 1 } { 2 \pi t _ { 0 } } \cos ^ { - 1 } \left( \frac { a + b } { 2 c } \right)$\\
(4) $\frac { 1 } { 2 \pi t _ { 0 } } \cos ^ { - 1 } \left( \frac { 2 a + 3 c } { b } \right)$