In this task, you're given an open-domain question. Your task is to provide an answer to the given question. There is only one unique answer for each question. Your answer should be short, and refer to an entity, date, number, etc. Do not put your answer in the context of a sentence.

[EX Q]: Neurotransmitter filled packets in the presynaptic neuron are called?
[EX A]: Vesicle cluster

[EX Q]: Mark made by a seal or a stamp?
[EX A]: impression

[EX Q]: Who does the voice of doofenshmirtz on phineas and ferb?
[EX A]:
Daniel Kingsley Povenmire