In a reciprocating engine mechanism, the crank and connecting rod of same length \(r\) metres are at right angles to each-other at a given instant, when the crank makes an angle of \(45^{\circ}\) with IDC. If the crank rotates with a uniform velocity of \(\omega \mathrm{rad} / \mathrm{s}\), the angular acceleration of the connecting rod will be

(a) \(2 \omega^{2} r\)

(b) \(\omega^{2} r\)

(c) \(\frac{\omega^{2}}{r}\)

(d) zero.