How many of the following on hydrolysis, give Methane
 i) ${\mathrm{Al}}_4{\mathrm{C}}_3$ ii) ${\mathrm{Mg}}_2{\mathrm{C}}_3$ iii) $B{e}_{2}C$ iv) ${\mathrm{BeC}}_2$  v) ${\mathrm{CaC}}_2$