Question

Which type of mutation is responsible for the change in the iRNA base?

Answer 1

A) silent - means that the letter changes but the outcome is the same
B) missense - means that it changes just one base pair
C) nonsense - changes something to a stop code and messes up the whole chain
D) insertion - adds a letter

so its A because you said "but during translation the iRNA strand still creates the same protein" so even though the mutation occurred the outcome was still the same.