You are given the following molecular formulae of some hydrocarbons: 

${\mathrm{C}}_5{\mathrm{H}}_8; {\mathrm{C}}_7{\mathrm{H}}_{14}; {\mathrm{C}}_6{\mathrm{H}}_6; {\mathrm{C}}_5{\mathrm{H}}_{10}; {\mathrm{C}}_7{\mathrm{H}}_{12}; {\mathrm{C}}_6{\mathrm{H}}_{12}$

(a) Which formula represents cyclohexane as well as hexene?
(b) Which formula represents benzene?
(c) Which three formulae represent open chain unsaturated hydrocarbons having double bonds?
(d) Which two formulae represent unsaturated hydrocarbons having triple bonds?
(e) Which three formulae can represent cyclic hydrocarbons?