Answer:
there is gain and  receive is $100 long term gain 
Explanation:
given data 
Sadie sold = 10 shares
Sadie sold shares of stock = $500
time = 16 year ago
Sadie purchased the stock = $600
time = 2 year earlier
George sells  stock = $700
to find out 
amount and character of his recognized gain or loss in the current year
solution
we know that George receives dual basis in the stock 
his loss  = $600 - $500 = $100 
and 
if we consider stock is sold at a gain
then  George receives a carryover basis = $600
and 
if we consider stock is sold at a loss
then  George receives  = $500
also here his sister basis and holding period is transfer to her brother 
so we can say there is gain 
and receive is = proceed - carryover basis 
 receive is = $700 - $600
 receive is $100 long term gain