"I have learnt a great deal working factories, and for a time I've never been a weaver. Here are my testimonials, Mr. Davis"

Answer: Option D

witnesses : a person who sees an event, typically a crime or accident, take place.
testaments : a person's will, especially the part relating to personal property.
tokens : a thing serving as a visible or tangible representation of a fact, quality, feeling, etc.
credentials : a document proving a person's identity or qualifications.
testimonials : a formal statement testifying to someone's character and qualifications.


Synonym of testimonials is credentials