Final answer:
The expression log base a of b times log base b of a simplifies to 1.
Step-by-step explanation:
The given expression is logab * logba. To simplify this expression, we can use the property that logab = 1 / logba. Therefore, the expression becomes:
 (1 / logba) * logba
 The logba in the numerator and the denominator cancel each other out, resulting in:
 1
 Therefore, the answer is a) 1.