The correct sentence is C) My jeans are new
Let's check all the variants.
A) His clothes were expensive.
Clothes are a plular noun. We use "were" with plular nouns. But we use "was" with nouns in singular.
B) He gave me 3 useful advice.
There is no such form like "advices". Advice always is singular noun. We don't use it in plular.
C) My jeans are new.
Jeans are plular. This is the correct variant.
D) The news was bad.
News is used always in singular. That is why we put "was", not "were".
E) There were 10 sheep on the farm.
There is no form like a "sheeps" too. Sheep doesn't change in plular form.
Sheep (singular) = sheep (plular).
The correct sentence is C) My jeans are new.
The correct sentence is C) My jeans are new
Let's check all the variants.
A) His clothes were expensive.
Clothes are a plular noun. We use "were" with plular nouns. But we use "was" with nouns in singular.
B) He gave me 3 useful advice.
There is no such form like "advices". Advice always is singular noun. We don't use it in plular.
C) My jeans are new.
Jeans are plular. This is the correct variant.
D) The news was bad.
News is used always in singular. That is why we put "was", not "were".
E) There were 10 sheep on the farm.
There is no form like a "sheeps" too. Sheep doesn't change in plular form.
Sheep (singular) = sheep (plular).
The correct sentence is C) My jeans are new.