因 \({a_n} = {2^n}\) , \({b_n} = {2^{{a_n}}} = {2^{{2^n}}}\) , \(\left( {1 + \frac{1}{{{b_1}}}} \right)\left( {1 + \frac{1}{{{b_2}}}} \right)\left( {1 + \frac{1}{{{b_3}}}} \right) \cdots \left( {1 + \frac{1}{{{b_n}}}} \right)\)
\( = \left( {1 + \frac{1}{{{2^2}}}} \right)\left( {1 + \frac{1}{{{2^{{2^2}}}}}} \right)\left( {1 + \frac{1}{{{2^{{2^3}}}}}} \right) \cdots \left( {1 + \frac{1}{{{2^{{2^n}}}}}} \right)\) \( = \frac{{\left( {1 - \frac{1}{{{2^2}}}} \right)\left( {1 + \frac{1}{{{2^2}}}} \right)\left( {1 + \frac{1}{{{2^{{2^2}}}}}} \right)\left( {1 + \frac{1}{{{2^{{2^3}}}}}} \right) \cdots \left( {1 + \frac{1}{{{2^{{2^n}}}}}} \right)}}{{1 - \frac{1}{{{2^2}}}}}\)
\( = \frac{{\left( {1 - {{\left( {\frac{1}{{{2^{{2^n}}}}}} \right)}^2}} \right)}}{{1 - \frac{1}{{{2^2}}}}} < \frac{4}{3} < 2\) .
故选:C.