Which statement describes a variable expense? (1 point)

Chrystal pays $120 each month for access to high-speed internet at
her house
Gemma's mortgage payment is exactly $784.56 every month.
John makes an $89 payment each month on his new mobile phone
Mia's electricity bill total depends on how much electricity she uses
each month.

Mia's electricity bill total depends on how much electricity she uses each month.