The correct option is
A These
The pronouns that demonstrate (point out) some particular persons or things are called demonstrative pronouns.
In the given sentence the shirts are being pointed out.
The demonstrative pronouns 'this', 'that' are referred to singular nouns.
The pronoun 'it' is not used to demonstrate any thing or person.
The demonstrative pronoun 'these' is used to indicate plural nouns.
Here, the plural noun 'shirts' are being referred to.
Thus option A is the correct answer. Options B,C,D are incorrect.