A Missense Mutation in Neurospora Will Revert by Treatment with Nitrous

Multiple Choice

A missense mutation in Neurospora will revert by treatment with nitrous acid,but not by hydroxylamine.Hydroxylamine (HA) causes only G·C → A·T transitions,while nitrous acid causes both G·C → A·T and A·T → G·C transitions.The original mutation (not the reversion) must have been:

A) AT to CG.
B) AT to GC.
C) AT to TA.
D) GC to AT.
E) GC to TA.