Answer
See the detailed answer below.
Work Step by Step
We know that the emf is given by
$$\varepsilon=\varepsilon_0\cos\phi $$
where
$$\phi=\omega t=2\pi f t$$
so at $t=60$ ms,
$$\phi =2\pi 60 (60\times 10^{-3})=\bf \frac{36\pi}{5}\;\rm rad$$
Converting to degrees,
$$\phi = \frac{36\pi}{5}\;\rm rad\times \dfrac{180^\circ}{\pi\;\rm rad}=\bf 1296^\circ$$
This means that it is not the first cycle, where the full cycle is 360$^\circ$.
So,
$$N=\dfrac{1296^\circ}{360^\circ}=3.6\;\rm cycle$$
where $N$ is the number of the cycles, it is in the fourth cycle at an angle of
$$\phi=0.6\times 360^\circ=\bf 216^\circ$$
So,
$$\varepsilon=\varepsilon_0\cos(2\pi f t)=170\cos 216^\circ =\bf -137.5\;\rm V$$
See the figure below.