Answer:
D). An inference.
Step-by-step explanation:
Context clues are demonstrated as the hints that are provided by the author to explain or clarify the meaning of an unfamiliar or unusual word to the readers or audience.
As per the question, 'an inference' exemplifies the type of context clue that could be employed to infer or deduce the meaning of the word through the use of logic or reason. Thus, the unfamiliar word 'malleable' logically implies the meaning 'flexible' as per the context and words surrounding it as given in the sentence(' 'it could serve as springs' and 'other were too hard'). Hence, 'an inference' i.e. option D is the correct answer.