So we need to get the five composers first?
No, you might realise the connection before you get all five, so you first have to look at what options there are for each named work (i.e. which composers wrote a fifth symphony, which composers wrote a Piano Trio in A minor, and a connection will become evident which will assist in identifying the remaining composers)
How about these?
Tchaikovsky – Piano Trio in A minor
Chopin – Mazurkas
Beethoven – Piano Concerto in C minor
Handel – Flute Sonata in D
No key signature for the symphony? How about Shostakovich – Symphony No.5?
Well done, the Tchaikovsky is correct