So you mean the preposition 'to' in #1 and 'across' in #2 after 'and' are optional. (that's why the sentence #2 is also correct as #1, isn't it?)
'It is said' by the exam question maker who used some source regarding prepositional verbs. Again, I think this question maker made a wrong(or at least ambiguous) question because you(native speaker) say #2 is not wrong.
So you mean the preposition 'to' in #1 and 'across' in #2 after 'and' are optional. (that's why the sentence #2 is also correct as #1, isn't it?) -- Yes, that's right.