Which statement correctly describes the relationship of ideas in this text?

The passage of time is signaled by the words "was committed" and "samples were distributed."
The passage of time is signaled by the words "he finally convinced" and "customers became."
Cause-and-effect relationships are signaled by the words "however" and "customers became."
Cause-and-effect relationships are signaled by the words "which 'met an unperceived need’" and "Early results."