gmat1978 wrote:Stanford researchers have shown for the first time that adult bone marrow cells have migrated to the brain and express neuronal-specific proteins that look like their neuronal neighbors who suggest that an individual's own, genetically-modifier bone marrow cells may someday be used to treat diseases like Parkinson's or Alzheimer's,or damage caused by a stroke or traumatic brain injury.

a) have migrated to the brain and express neuronal-specific proteins that look like their neuronal neighbors who suggest
b) can migrate with their neuronal neighbors who express neuronal-specific proteins, which suggest
c) are migrating to their neuronal neighbors and expressing neuronal-specific proteins which can look like their neuronal neighbors and that is what is suggesting
d) are migrated to the brain and express neuronal-specific proteins that look like their neighbors and that can suggest
e) can migrate to the brain, express neuronal-specific proteins, and begin to look like their neuronal neighbors, suggesting

Can anyone please help me figure out what(Tense, parallelism etc) is wrong with each of the answer choices?

OA after some discussion

Thanks

gmat1978 wrote:In this problem, how would I go about finding out the appropriate tense (have migrated / can migrate / are migrating / are migrated). Generally, I look at the context to figure out the tense. But in this problem, I am confused and not able to figure out the correct tense. If anyone can please explain with examples, that would be very helpful.

Thanks