In Leber's Disease (LHON),degeneration of the Optic Nerve Results in Blindness

Multiple Choice

In Leber's disease (LHON) ,degeneration of the optic nerve results in blindness due to a defect in NADH dehydrogenase affecting electron transport.If this is due to a mutation in a mitochondrial gene,which combination of effects would you expect to see when doing a pedigree analysis of a family with LHON? i. variable expressivity
Ii. incomplete penetrance
Iii. progressive blindness over time
Iv. maternal inheritance
V. diminished muscle mass

A) i and ii only
B) ii and iii only
C) iii and iv only
D) i,ii,iii,and v only
E) i,ii,iii,and iv only