My teacher was a lot of help (sarcasm). Basically named half the speeches could possibly be specified, but i suppose she gave reasons to back up her claims. These are the ones I'd agree with.
Keating - Short, everyone knows.
Deane - The easiest speech, most likely everyone in the state would've studied it.
Bandler - Apparently HSC exams are written near beginning of the year (?) So since this is a relatively short, new speech, and also because of the recent context with Rudd's apology, she thought this might be selected.
I feel the only speech that would kill everyone if it was specified is Atwood's