In filter-feeder chordates, which structure has a mucus sheets that capture nutrients suspended in the water?

Question

a)notochord

b)differentially permeable membrane

c) gill slits

d)filiform tongue

e)jaw

thanks!!

Answer 1

b)

Answer 2

Having spent five years doing research on a PhD dissertation with filter feeding chordates, I can tell you the answer is certainly c.  

They use a mucus sheet over their pharyngeal basket that contains their gill slits.