Bass clarinet fingering?

Question

Theres a note that is on the line, five lines under the measure, a b flat wats the fingering

Answer 1

sorry, but i don't think there's a bass clarinet fingering for that note. you'll just have to play it up an octave. i don't know how contrabass clarinet music looks like but it might be for that instrument instead.

Answer 2

5 ledger lines below the staff in treble clef is a B (Bb if in the key signature).

There isn't a bass clarinet made with that range.  The lowest is the C right above it and most bass clarinets don't have a C extension.  You can achieve that tone for 'special effect' if you have an instrument with a C extension by (I know, it sounds crazy - but it works) putting your heel in the bell (take your shoe off) and playing the low C while lipping down a half step and adjusting your heel position for tuning.  It's not for everyday use - it's a special effect.

Five ledger lines below the staff in bass clef is a D and a bass clarinet with a low C extension can reach that note.  It really should have been written in treble clef or an octave higher though.  On most bass clarinets with a low C extension - that D will be a right thumb key.  On some it's a right pinky key at the bottom.

If you're playing on a regular bass clarinet with range to low Eb, raise the entire line/phrase an octave.  It's possible someone was arranging in sounding range instead of written range.  Remember, your instrument sounds an octave+ (major 9) lower than it's written.

ADD: a contra part is written in the same range as a bass part but sounds an octave lower than the bass.  The contra can't reach that low Bb (as written) either.  Most professional contra clarinets have a C extension but most players aren't using a professional instrument and can only reach to the written Eb below the staff.