Using the Quotient Rule of Integer Exponents, when you divide two expressions with the same base, you subtract the exponents.
The rule states: \[ \frac{a^m}{a^n} = a^{m-n} \]
In this case, you have: \[ \frac{t^{400}}{t^{100}} = t^{400 - 100} = t^{300} \]
So, the simplified expression is: \[ t^{300} \] Therefore, the correct response is t^300.