Answer:
Mark should include in the letter to avoid litigation charges:
Specific facts about the consultant that can be verified.
Step-by-step explanation:
False information, sentiment-hurting statements, or personal opinions about the consultant's character should never be found in formal letters that are meant to offer constructive criticisms. This means that only specific facts that are verifiable should be included. Formal letters are not avenues for character defamation. They are called "formal" because they must stick to specific and relevant official purposes.