Molar mass of ${\mathrm{S}}_8$ molecule is .

The IUPAC name of  ${\mathrm{CH}}_2=\mathrm{CH}-\mathrm{CH}={\mathrm{CH}}_2$ is _____.

$$\begin{gathered} \mathrm{A}: \mathrm{Buta}-1, 3-\mathrm{diene} \\ \mathrm{B}: \mathrm{Buta}-1, 2-\mathrm{diene} \\ \mathrm{C}: \mathrm{Buta}-1, 3-\mathrm{triene} \end{gathered}$$

Enter your correct answer as $\mathrm{A}, \mathrm{B} \mathrm{or} \mathrm{C}$