A useful technique here is to recall encomium from its typical usage: it almost always appears alongside words like "tribute," "praise," or "commendation," often in the context of honoring someone's achievements, sometimes posthumously.
Scanning the options for a word used in the same context of honoring achievements or memory, eulogy stands out immediately, since it is the standard English term for a speech of praise given especially at a person's funeral or in their honor.
The remaining options fail this context test: verve describes energetic style rather than content of praise, doggerel is a term of criticism for bad poetry, and force is a physical or abstract term about power, with no link to praise or tribute.
Let's summarize:
Matching the "context of usage" rather than just literal dictionary meaning often narrows down tricky synonym options quickly.