Composition of fabric blends?

For my dad, who still bears a grudge against The Master, because he submitted this question years ago…(I think it’s a dumb question, but hey, he’s standing behind me, so please humor him…)

If you have, say, a 35% poly/65% cotton fabric, does that mean each thread is 35% poly and 65% cotton, or that 35% of the individual threads are poly and 65% are cotton?

(I guess A, because B would make the pabric pucker when it shrank.)

Please don’t disappoint me, O Teeming Millions!

I am 99% sure that it means that each thread is made of a combination of cotton and polyester.

http://www.vardhmanthreads.com/know_our_threads1.htm

Polycotton yarns are spun from a mixture of cotton and polyester fibers.
Look at how the discussion below is phrased in terms of yarn rather than fabric:

The Mystery of Fibrillation: When substrate fibers break loose

Sounds like it would make a fascinating horror movie!