Solution
= Solution
Taking the ratio of the supplied <primordial tensor power spectrum> and scalar spectrum cancels the common factor $(H/2\pi)^2$:
$$
r=\frac{8}{M_{\rm Pl}^2}
\frac{\dot\phi^2}{H^2}
=16\epsilon.
$$
To first slow-roll order $\epsilon=\epsilon_V$, so the <tensor-to-scalar ratio> is
$$
\boxed{r=16\epsilon_V},
\qquad
\boxed{C=16}.
$$