1.Results indicated positive paths from A to B, B to C, and C to A and B.
2.Results indicated positive paths from A to B, from B to C, and from C to A and B.
Which of the above sentences is considered grammatically correct? Is it necessary to repeat "from" after the comma and/or the conjunction "and"?
I'd like to know what would be considered correct in American English, if it makes any difference.