How many molecules are acidic oxides among the following:

$\mathrm{C}\mathrm{O},\mathrm{ }\mathrm{N}{\mathrm{O}}_2,\mathrm{ }\mathrm{S}{\mathrm{O}}_2,\mathrm{ }\mathrm{S}{\mathrm{O}}_3,\mathrm{ }\mathrm{N}\mathrm{O},\mathrm{ }{\mathrm{N}}_2\mathrm{O},\mathrm{ }\mathrm{S}\mathrm{i}{\mathrm{O}}_2,\mathrm{ }\mathrm{C}{\mathrm{l}}_2{\mathrm{O}}_7$

• A

  $4$
• Correct answer
  B

  $5$
• C

  $6$
• D

  $7$

Hence, the correct answer is option: 'B'.