Sorry Flippineck, I didn't realise this was homework. I just read some of the last posts and responded to them.
This question is a bit like asking "Two identical cars are travelling in convoy north along a single lane road at 60 miles per hour. Another identical car is travelling south towards them at 60 miles per hour. After the inevitable head-on collision, what is the velocity of the cars?"
I think you can see that there are far more variables than you can easily cater for.
In this case, the new fresh batteries would practically have a voltage of more than 1.5V, but even ignoring this, Laplace has pointed out that any typical values you might assume will not necessarily apply to all of the batteries in this question.
Personally, I would take option 4, (V=?) because I am not certain it would be any of the other voltages listed. However, there are 2 of the remaining three answers which are more likely more incorrect than the other.