Answered

A secondary source is most likely reliable and credible if it is:

Acreatively written and published on a blog.
Bwritten by a student and posted to his individual website.
Ccreated by an educated expert and published in an academic journal.
Da firsthand account published in a magazine.

Verified Answer :

Neuron

A secondary source is more likely to be reliable and credble if it's created by an educated expert and published by an academic journal - compared to the other possibilities listed here. C is the correct answer.

DavidCor96

A secondary source is most likely reliable and credible if it is:

C. Created by an educated expert and published in an academic journal.

For an article or research paper to be reliable, secondary sources from educational websites or articles written by experts must be taken into consideration.  

Since these secondary sources give strong support to the researcher's main statements, his/her research article or essay acquires enough validity.