请教一到LSAT逻辑

江南天阔

第二套。
All intelligent people are nearsighted. I am very nearsighted. So, I must be genius.
问：
Which of the following exhibits both of the logical flaws exhibited in the argument above?

B. All chicken have beaks. This bird has a beak. So, this bird must be a chicken.

D. John is extremely happy. So, he must be extremely tall because all tall people are happy.

答案是D。 我也同意。但
B为什么不对？

merlion

原题：intelligent->nearsighted
      genius<-nearsighted  (genius>>intelligent)

(d) tall->happy
    extremely tall <-extremely happy  (extremely tall>>tall)

(b) chicken ->beaks
    chicken<-beak    没有第二个逻辑错

江南天阔

I got it . Thanks .