Rhetorical Devices are techniques that uses specific structure in sentences to persuade the audience or to obtain the desired effect.
The correct options are:
2. Without a solution, we are in trouble. Without a solution, the trouble will be great.
Rhetorical Device: Anaphora
In the option 2 the writer uses Anaphora, which consists in repeating the same words (In this case "Without a solution") at the beginning of successive sentences, this rhetorical device is often used in speeches to emphasize an idea.
3. We do not need a solution right away, since two days is plenty of time to solve this global issue.
Rhetorical Device: Verbal Irony
In option 3 the writer uses Verbal Irony, which consists in saying something opposite to what you truly mean. In verbal irony there must be an indication that the meaning was not meant, in this case the writer says "two days is plenty of time to solve this global issue" as an indication that a solution right away is actually needed, and that the writer is being ironic.