Answer:
O A. It is highly personal and makes assumptions about other people's feelings.
Step-by-step explanation:
The credibility of any historical source depends on the nature of the source. If it is an unbiased and have a valid proof of the claim/ argument made, then we can say that the source is credible.
On reading the given passage, we can safely assume that it is not a credible source. One, because it contains a highly personal opinion of the Haitian Revolution. And two, it makes assumptions about the feelings of others, especially the slaves "who worked on [his/her] plantation". The speaker felt that the slaves in his plantation "were much happier before the plantation [.. and would] like things to go back to the way they were". This personal and assumptive opinion makes it easy for historians to question the source's credibility.
Thus, the correct answer is option A.