A circle has a radius of log10(a2) and a circumference of log10(b4). What is logab?
<spanclass=′latex−bold′>(A)</span>4π1<spanclass=′latex−bold′>(B)</span>π1<spanclass=′latex−bold′>(C)</span>π<spanclass=′latex−bold′>(D)</span>2π<spanclass=′latex−bold′>(E)</span>102π