求助一道GWD数学题

Rainbeauty

One kilogram of a certain coffee blend consists of x kilogram of type I coffee and y kilogram of type II coffee.  The cost of the blend is C dollars per kilogram, where C = 6.5x + 8.5y.  Is x < 0.8?
(1)      y > 0.15
(2)      C ≥ 7.30
答案给的B
但是我觉得B 只能推出x最多是小于1点几的 不sufficient呀。。。
球NN解释

844756705

6.5x+8.5y=C≥7.3;

6.5x+8.5(1-x)≥7.3;

                    x≤0.6
所以B应该是对的吧~