Choice D is correct. Average =31​(3.2+1247​+310​). The decimal 3.2=100320​=516​, and the lowest common denominator of the three fractions is 60 , then 516​=60192​,1247​=60235​, and 310​=60200​. Then, 31​(60192​+60235​+60200​)=31​(60627​)=60209​.