Lido manufactures A and B from a joint process (cost = $80,000). Ten thousand pounds of B can be sold at split-off for $15 per pound or processed further at an additional cost of $20,000 and later sold for $16. If Lido decides to process B beyond the split-off point, operating income will:

increase by $10,000.

increase by $20,000.

decrease by $10,000.

decrease by $20,000.

decrease by $58,000.

show work please