The intensifier 'too' is an adverb that must precede an adjective such as too pretty, too hard, too strong, etc. However, Option A and B are nouns while C and D are adjectives. Note that verbs in their past participle form can function as adjectives. Option D is the correct answer and most suitable because while 'compliable' is no longer in use 'complicated' is still very much in use and its meaning is in coherence with the sentence structure.