To convert 0.27 to a rational number in simplest form, we need to express 0.27 as a fraction.
0.27 can be written as:
\[ \frac{27}{100} \]
Next, we check if this fraction can be simplified. The numerator is 27, and the denominator is 100. The greatest common divisor (GCD) of 27 and 100 is 1, which means that \(\frac{27}{100}\) is already in simplest form.
Thus, the correct answer is:
\[ \frac{27}{100} \]