(Choose 1 answer)
Consider a spatial database that consists of 1000 records. If an item A appears 200 times in the database and the rule "if A, then B" appears 100 times, what are the support and confidence for the rule "if A, then B"?
A. support: 10%; confidence: 50%
B. support: 20%; confidence: 50%
C. support: 20%; confidence: 20%
D. support: 20%; confidence: 10%
