In this task, you're given a question, along with a context passage. The passage will not have a direct answer to the question, but can include some information and a clue for the answer. Assuming you can only obtain information about one entity in the passage, your job is to determine whether information from the passage can be used to answer the question. Indicate your choice as `a` for Yes or `b` for No.
Q: Question: which phase of sleep is the longest? Passage:Von Economo, in his studies, noticed that lesions in the connection between the midbrain and the diencephalon caused prolonged sleepiness and therefore proposed the idea of an ascending arousal system. During the past few decades major ascending pathways have been discovered with located neurons and respective neurotransmitters. This pathway divides into two branches: one that ascends to the thalamus and activates the thalamus relay neurons, and another one that activates neurons in the lateral part of the hypothalamus and the basal forebrain, and throughout the cerebral cortex. The cell group involved in the first pathway is an acetylcholine-producing cell group called pedunculopontine and laterodorsal tegmental nucleus(PPT/LDT). These neurons play a crucial role in bridging information in between the thalamus and the cerebral cortex. These neurons have high activation during wakefulness and during REM sleep and a low activation during NREM sleep. The second branch originates from monoaminorgenic neurons. These neurons are located in the locus coeruleus, dorsal and median raphe nuclei, ventral periaqueductal grey matter, and tuberomammillary nucleus. Each group produces a different neurotransmitter. The neurons in the locus coeruleus produce noradrenaline, as fore the neurons in the dorsal and median raphe nuclei, ventral periaqueductal grey matter, and tuberomammillary nucleus produce serotonin, dopamine and histamine respectively. They then project onto the hypothalamic peptidergic neurons, which contain melanin-concentrated hormones or orexin, and basal forebrain neurons which contain GABA and acetylcholine. These neurons then project onto the cerebral cortex. It has also been discovered that lesions to this part of the brain cause prolonged sleep or may produce coma.

A: 
a