Neurodegenerative diseases were once considered disorders of the mind

A. The limbic system and the olfactory ensheating cells are one of the many target areas where viruses like to reactivate.

Incorrect: Inconsistent. The passage clearly states that the OECs guide the virus to their targets and one such target is the limbic system, where viruses like to reactivate. Therefore, the OECs themselves cannot be the targets.

B. The regeneration of the OECs is linked with the spread of the HHV-6 virus.

Correct. This piece of information is given in the last two sentences of the passage. The author states the neurogenesis provides the virus the opportunity to spread.

C. The smell sensing neurons guide the HHV-6 virus to potential targets in the nervous system.

Incorrect: Out of Scope. As stated in the explanation of the first choice, the OECs guide the virus to targets in the nervous system. There is no information given regarding a similar role of the smell sensing neurons.

D. An inactive reservoir of HHV-6 in the body is indicative of the person’s lack of susceptibility to neurodegenerative diseases.

Incorrect: Out of Scope. The author states that in healthy people the virus, though present, is inactive. Nothing is given regarding their likelihood of developing any kind of neurodegenerative disease.

E. Viruses like to flourish in deep, humidity ridden areas.

Incorrect: Out of Scope. This information is completely out of scope and not given in the passage.



A. To indicate that it is extremely difficult to stop infection through the nasal passage.

Incorrect: Irrelevant. The author is not concerned with all kinds of infections through the nasal passage.

B. To prove that there is a greater likelihood of multiple sclerosis in people who have active strains of virus rather than those who do not.

Incorrect: Irrelevant. The comparison regarding the probability of developing the disease is neither discussed nor indicated.

C. To illustrate that HHV-6 infects in the same manner as most other viruses do.

Incorrect: Irrelevant. Again, no such comparison is made between the HHV-6 virus and other viruses.

D. To explain the finding that the samples of both the mentioned groups showed the presence of HHV-6.

Correct. This answer correctly encapsulates the reason the author make the cited statement.

E. To indicate that there is a chance that the occurrence of multiple sclerosis may increase in the future if the strains of HHV-6 are activated.

Incorrect: Irrelevant. No such likelihood is discussed anywhere in the passage.



A. Those who possess higher concentrations of HHV-6 in the olfactory bulb are at a high risk of developing multiple sclerosis.

Incorrect: Out of Scope. The author gives no information to deduce anything regarding the chances of such people developing the disease.

B. Those who have a sharper sense of smell are at a greater risk of multiple sclerosis.

Incorrect: Out of Scope. The author neither mentions nor indicates towards any such relationship. The sense of smell is mentioned in the last sentence of the passage in a completely different context.

C. The absence of multiple sclerosis in a person does not necessarily indicate an absence of the disease causing virus in that person

Correct. This information can be deduced on the basis of the findings mentioned in the passage and the author’s statement to explain the findings. As per the author it is not uncommon to have dormant reservoirs of the virus. The author draws this statement to explain the findings of the study that showed that samples from both healthy and diseased tissues showed the presence of the virus.

D. Multiple sclerosis, alongwith other neurodegenerative diseases, can have disease causing viruses lying dormant in the human body without any external symptom of the same.

Incorrect: Partial Scope. The passage gives no specific information about the viruses causing other neurodegenerative diseases for us to be able to deduce the following portion of the answer choice :

alongwith other neurodegenerative diseases

E. In the absence of the limbic system, it would be difficult for the HHV-6 virus to reactivate.

Incorrect: Out of Scope. Although the limbic system is described as a place where viruses like to reactivate but the limbic system is only one of many targets for the virus. So, we do not know where else the virus could/would reactivate.