Concept:Convert binary numbers to decimal by summing each digit multiplied by its positional power of 2.Explanation:Convert (1000000001)2 to decimal: 1×29+1×20=512+1=513.Convert (0.0101)2 to decimal: 1×2−2+1×2−4=41+161=165=0.3125.Subtract: 513−0.3125=512.6875.Thus the result in base‑10 is (512.6875)10.Answer:(512.6875)10 (Option B).