Volume coefficient $\propto$ is given as
$V_{\large\circ} = K\times273.15$
$V_t = K\times(t+273.15)$
$\therefore \large\frac{V_t}{V_{\large\circ}} = \large\frac{t+273.15}{273.15}$
$=[1+\large\frac{t}{273.15}]$
$Or\; V_t = V_{\large\circ} [1+\alpha t]$
Where $\alpha = \large\frac{1}{273} = 3.66\times10^{-3}$
Hence answer is (b)