Whereas logic bombs viruses are

time bomb viruses are

triggered when specific logical conditions are met $-$ viruses hidden on web sites in the form of scripts

viruses hidden on web sites in the form of scripts $-$ triggered when a certain passage of time is met

triggered when a certain passage of time is met $-$ triggered when specific logical conditions are met

triggered when specific logical conditions are met $-$ triggered when a certain passage of time is met.

viruses that attach themselves to documents that use macros $-$ triggered when a certain passage of

time is met