Final answer:
The expression log2(r) - log2(t) simplifies to log2(r/t), utilizing the property that the logarithm of a quotient is the difference of the logarithms.
Step-by-step explanation:
The expression log2(r) - log2(t) can be simplified using the properties of logarithms. According to one of the basic properties of logarithms, the logarithm of the number resulting from the division of two numbers is the difference between the logarithms of the two numbers. So the expression log2(r) - log2(t) simplifies to log2(r/t), which corresponds to option a) log2(r/t).