Final answer:
Monica refers to Christine as 'old-fashioned' based on the phrase used in the dialogue.The correct option is A.
Step-by-step explanation:
In the dialogue, Monica uses the phrase “Oh, you old fashioned little dear” to describe Christine. This indicates that Monica is calling Christine old-fashioned. Therefore, the correct answer to what Monica calls Christine in the dialogue is a) Old-fashioned. None of the other options provided, such as trendy, fashionable, or stylish, align with the phrase used by Monica. The term old-fashioned typically implies adherence to traditional values or styles, which may be regarded as out of date or not following current trends.