<prompt> Best investigation for prostate cancer is -Prostate Specific AntigenAcid PhosphatsePSA velocityAlkaline phosphatase  <response>: Answer- C. PSA velocityFor men with a PSA above 4, PSA velocity of more than .75 ngml year is suggestive of Ca.While for those with lower PSA levels, rates above 0.5 ngml per year should be used to advise biopsy. 