Believing an article about financial investments because the author has a PH.D. in economics.Which one is the best answer? a. is the account...

I moved your question to the "Reference" section as you
are asking on whether a source is to be valid on the grounds of their preparation,and
there is no other tag than Reference for it.

OK- It seems
that you are asking why should we trust a source based on his or her educational level.
The answer is A, but you have to consider B and this is
why:

Surely a Ph.D (I am one myself) has learned about
biased research, and knows about limitations, validity, and much more when it comes to
investigation.

Because of this, I tend to lean to A, since
(regardless of the source) you have to ensure that whatever educational level is at
stake, the source MUST remain objective and impartial.

I
also mentioned B because it is a continuum of A: If you are partial you will tend to
leave out info. So, ensure that your source (whatever degree they have) is objective and
focused. So, I will stick to A, and watch out for B.