See the multi-choice question below:

Sentence 1: Rothschild's lack of familiarity with evolutionary theory may not be obvious to uninformed readers--his book bristles with ostentatious footnotes and seemingly learned references.

Sentence 2: Rothschild's lack of familiarity with evolutionary theory is down to his incompetency.

If the first sentence is true, then is the second sentence true?
Options are:
+ yes
+ it is not possible to tell
+ no
it is not possible to tell