Answer: Option C.
Explanation: The running out of breath problem is primarily depending on the breathing technique of the player.
A bad fingering technique may affect the sound, but not the technique (while someone with a bad finger technique may also have a bad breathing technique)
The intonation of the clarinet will affect the sound, some notes will go flat or sharp.
For the tuning we are in the same case if the clarinet is not tuned correctly, the player may sound out of tune with respect of the rest of the band, but it should not affect the breathing of the player.
And for these two things (intonation and tuning), clarinets may go sharp or flat depending on the temperature, so these two things are kinda common problems for clarinet players.
So the right option is C, the piece has too many long phrases, and the player can not breathe properly in these long phrases.