A set contains _{$\text{(2n + 1) }$} elements. The number of subsets of the set which contain at most _{$\text{'n' }$} elements is

• A

  _$\text{2n}$

• B

  _{${\text{n}}^{\text{2}}$}

• C

  _{${\text{2}}^{{\text{n}}^{\text{2}}}$}

• D

  _{${\text{2}}^{\text{2n}}$}