1. a is closer to b than c. so in this case assume b=2 c=3 a=1 then we have b+c/2=2.5 > a(=1)

also , say b=4 a=5 c=3 then we have b+c/2=3.5 < a(=5)

Insufficient.

2. b>c insufficient as there is no relationship mentioned between a ,b and c.

Together 1 &2 , since a,b,c>0 and b>c and a is closer to b than c , we have a midpoint between b and c which is always less than a . i.e

b+c/2<a since a is much closer to b than c.

Eg: assume c =0.1 ,b=0.2 and a =0.06 (closer to b) or 0.3 which is > b+c/2 =0.05

Sufficient.

So Ans is C

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