What is the BEST description of malware that will execute some malicious activity when a particular condition is met (i.e., if the condition is met, then executed)?

A logic bomb performs malicious actions when a specific condition or conditions are met. A boot sector virus infects the boot sector of the hard drive. A buffer overflow happens when the attacker tries to put more data in a variable than it can hold. A sparse infector virus performs its malicious activity intermittently to make it more complex to detect.