A firm$$s computer systems are flooded with thousands of seemingly legitimate requests, the sheer volume of which will slow or shut down the site$$s use. This might be caused by receiving spam from thousands of difficult$-$to$-$shut$-$down accounts. This is an example of

a$.$

Data harvester

b$.$

Malware Attacks

c$.$

DDoS attack

d$.$

Stealing financial data

e$.$

Cash$-$out fraudster