Answer:
A. $20,000 
Step-by-step explanation:
Lynn 60,000
Marty 80,000
Nancy  70,000 
Total 210,000
The buyout for nancy consist in:
capital balance + Nancy share of unrecorded goodwill
76,000 = 70,000 + 6,000 nancy goodwill
Nnacy share income ratio is 30% so total goodwill is:
6,000/30% = 6,000 / 0.3 = 20,000
The journal entry will be:
goodwill 20,000
Nancy Account 70,000
 Cash 76,000
 Lynn 8,000
 Marty 6,000