$A$ hydrocarbon with molecular formula $C_4H_6$ undergoes the following reactions:
$A$. Decolourises molecular bromine.
$B$. Reacts with $HBr$.
$C$. Addition of ozone and then cleavage of the ozonide by $Zn / H_2O$ gives the product $C_4H_6O_2$.
Then,the structure of the hydrocarbon is:

• A
  Cyclobutene
• B
  None of these
• C
  $CH_3CH_2C \equiv CH$
• D
  Methylenecyclopropane