Answer:
$900
Step-by-step explanation:
South's deductible casualty loss = $900
Fair market value before the flood 18500
Fair market value after the flood (2000)
Decline in FMV 16500
Cost basis 20000
Lesser of basis or decline in FMV 16500
Minus: Insurance proceeds (13000)
Net loss 3500
Minus: $100 Floor (100)
10% of AGI (2500)
Deductible Loss 900