Fill in the blank with the most appropriate option.
_________ a pencil in my bag which you can borrow.
(a)that’s
(b)what’s
(c)it’s
(d)there’s

Hint: The sentence is simply letting us know that the bag contains a pencil which the person can borrow. It is letting us know of its existence. This means we need a specific adverb.

Complete answer: An adverb is a word or phrase that modifies or qualifies an adjective, verb, or other adverb or a word group, expressing a relation of place, time, circumstance, manner, cause, degree, etc. (e.g., gently, quite, then, there ).
We just need to find an option that also fits into the context of the sentence while being meaningful with the given sentence.

Now, we know what we are looking for. Let’s look at the given options:
(a)that’s - This word is a contraction of the words ‘that’ and ‘is’. This is a word that could be used in the given sentence, however, the sentence would feel incomplete. This word is not the required answer. So, this is an incorrect option.
(b)what’s - This word is a contraction of the words ‘what’ and ‘is’. This is a word that could be used in the given sentence, however, there is no question mark at the end of the sentence. This is not the required answer. So, this is an incorrect option.
(c)it’s - This word is a contraction of the words ‘it’ and ‘is’. This word would also feel incomplete to use in the given sentence, as it doesn’t fit into the context. This word is not the required answer. So, this is an incorrect option.
(d)there’s - This word is a contraction of the words ‘there’ and ‘is’. This word fits perfectly into the context of the given sentence. This is the required answer. So, this is the correct option.

Note: Identify the structure of the sentence, and the parts of speech used. They are in a particular order. Now, use the trial and error method and see which option best fits into the sentence.