In this sentence, "do you prefer", will come in the blank, as a question is being asked in the sentence and it is interrogative sentence.
What are interrogative sentences?
Interrogative sentences are the sentences in which a question is being asked or raised. These sentences end with a question mark.
In the statement, "Which __________, this kind of seminar or computer based training?", do you prefer will come in the blank, as the statement ends with a question mark, so it is a interrogative sentence.
Therefore, option, A, 'do you prefer', is correct.
Learn more about, interrogative sentences, here,
https://brainly.com/question/6324781
