To simplify the expression \( \frac{t^{400}}{t^{100}} \) using the Quotient Rule of Integer Exponents, we follow this rule:
\[ \frac{a^m}{a^n} = a^{m-n} \]
Applying this rule:
\[ \frac{t^{400}}{t^{100}} = t^{400 - 100} = t^{300} \]
Thus, the simplified expression is:
\[ t^{300} \]
So the correct response is:
t300 (t superscript 300 baseline).