Why did northern farm owners not support slavery? Slaves did most of the work on northern farms.
Northerners didn’t own farms.
Northern farms were small enough for owners to get all the tasks done without the help of slaves.
They knew the abolition of slavery would hurt the south more than it would help the north.

I am questing its 3 or 4  

Explanation:

here my reason for 3

Did the North have small farms?

The majority of people lived on small farms and found that much of the land was suited for subsistence farming—raising food crops and livestock for family use—rather than producing goods to export, or send to other countries.

here my reason for 4

NA ww SAN Northerners Against Abolition As you have learned, abolitionists were one interest group in the controversy over slavery. Their view was that slavery had to end. feared that African Americans might come north and take their jobs by working for low pay

4 Northern farms were small enough for owners to get all the tasks done without the help of slaves.

Explanation:

i ha the excact same question as you and i just guessed and got it right ... the quiz was due a month ago :|