Answer:
B). Predicate adjective.
Step-by-step explanation:
As per the question, the word 'simple' in the given sentence function as a 'predicate adjective' in the sentence as it modifies the subject 'Calculus problems' and follows the linking/connecting verb 'seemed'. Such adjectives are contrary to 'attributive adjective' which is placed right before the noun it qualifies or describes. Predicate adjectives instead follow the linking verb and describe the subject by detailing its appearance, nature, etc. Similar to the given example where 'predicate adjective' qualifies the nature of the subject 'Calculus problems' as 'simple'. Thus, option B is the correct answer.