B) the price the store pays for hd headphones if it spends a total of $2,000 on headphones and
buys 55 basic headphones for $20 each.

$900
Explanation:
I assume you’re asking for how much the store pays for HD headphones.
Given:
$2000 total for all headphones
55 basic headphones for $20 each

Total amount for BASIC headphones:
=> 55 x $20
=> $1100

Amount for HD headphones:
=> total amount of headphones - amount for BASIC headphones
=> $2000 - $1100
= $900

Delta airlines or untied airlines