To simplify the expression \( a^{67} b^{34} \), we need to consider whether we can factor or reduce it in any way.
However, since there are no common factors or terms that we can simplify further, the expression remains as it is.
So the simplest form of the expression \( a^{67} b^{34} \) is:
a^{67} b^{34}
If your goal is to express it differently or in a fraction form, it could also be rewritten as:
\[ \frac{a^{67}}{b^{34}} \]
But as it stands, without further context or operations, the answer remains the same:
a^{67} b^{34}
None of the other options provided simplify the expression correctly.