c$.$ Are events A and $B$ independent?

$22.$ Fraud detection has become an indispensable tool for banks and credit card companies to combat fraudulent credit card transactions. A fraud detection firm raises an alarm on $5\%$ of all transactions and on $80\%$ of fraudulent transactions. What is the probability that the transaction is fraudulent if the firm raises an alarm? Assume that $1\%$ of all transactions are fraudulent.