The correct option is B a
As per the rules of use of the indefinite article, the indefinite article is used in its original numerical sense of one i.e. to denote that there is a single object indefinite article can be used to replace the use of number 'one', here it can be used to denote one tie. The choice between indefinite article ‘an’ and ‘a’ is determined by the sound of the noun. Before a noun beginning with a vowel sound ‘an’ is used. Therefore Option B is incorrect. ‘A’ is used for nouns the sound of which begins with a consonant, since ‘tie’ begins with a consonant sound ‘t’, Option C is the correct answer. The definite article 'the' cannot be used in this question because it is not clear from the context which specific tie the speaker is talking about, thus Option A is incorrect. Option D 'some' cannot be used here because it is not an article and also because the word 'some' cannot be used with a singular/countable noun.