Re-arrange the following parts of a sentence in their correct sequence to form a meaningful sentence.

(A) for organizations which provide
(B) services to customers on a face-to-face basis,
(C) employees with whom they deal is very important
(D) the quality of the relationship between customers and

The correct option is (A), (B), (D), (C).

Let's analyze the sentence structure and the logical connection between the given parts to form a coherent and grammatically correct sentence:
1. Part (A) starts the sentence by introducing the context: "for organizations which provide". This sets up a prepositional phrase.
2. Part (B) logically follows Part (A) to complete the description of the organizations: "services to customers on a face-to-face basis,". Together, (A) and (B) form the introductory clause: "for organizations which provide services to customers on a face-to-face basis,".
3. Part (D) starts the main clause of the sentence, introducing the subject: "the quality of the relationship between customers and". This subject needs a completion pointing to the other party in the relationship.
4. Part (C) provides the completion for the subject and the predicate: "employees with whom they deal is very important". The word "employees" connects directly with "and" from the end of part (D), making the full phrase "relationship between customers and employees". The verb phrase "is very important" completes the sentence.

Combining all parts in the sequence (A) → (B) → (D) → (C) gives:
"For organizations which provide services to customers on a face-to-face basis, the quality of the relationship between customers and employees with whom they deal is very important."
This forms a grammatically correct and meaningful sentence.