A detector is placed near a radioactive isotope and records a count rate of 700 counts/min.
The half-life of the isotope is 8 min.
The average background count rate is 60 counts/min.
What is the count rate measured by the detector after 16 min?
(A) 100 counts/min
(B) 160 counts/min
(C) 175 counts/min
(D) 220 counts/min