175- People used to work very long hours but now they don't work ……. many hours.
a)enough b) such c)so d) too

ولماذا ؟

so

is the answer

So + Many / Few + Plural Noun
USE

"So" can be combined with "many" or "few" plus a plural noun to show extremes in amount. This form is often used in exclamations.

Examples:
I never knew you had so many brothers!
She has so few friends! It's really quite sad.