An organic compound A (C₅​H₈​) on hydrogenation gives compound B (C₅H₁₂​). Compound A on ozonolysis gives methanal and 2-ketopropanal. The compound A is:

a) 2-methyl-1-butene
b) 1,3-pentadiene
c) 2-methyl-2-butene
d) Cyclopentene