Principles will replace principals because –
Principal (Adj./Noun) : the most important; main
principle (Noun) : a moral rule or a strong belief that influences your action.
Look at the examples given below :
New roads will connect the principal cities.
He has high moral principles.
Hence, by the principles is the right usage

Correct Option: B

Principles will replace principals because –
Principal (Adj./Noun) : the most important; main
principle (Noun) : a moral rule or a strong belief that influences your action.
Look at the examples given below :
New roads will connect the principal cities.
He has high moral principles.
Hence, by the principles is the right usage

was will replace is because –
the Reporting Verb is in Past Tense. In Indirect Speech, the Reported speech changes into Past Tense when the Direct Speech is in Present Tense.
Look at the examples given below :
He said, “I am going to office.” (D.S.)
He said that he was going to office. (I.S.)
Hence, he was at fault is the right usage

Correct Option: C

was will replace is because –
the Reporting Verb is in Past Tense. In Indirect Speech, the Reported speech changes into Past Tense when the Direct Speech is in Present Tense.
Look at the examples given below :
He said, “I am going to office.” (D.S.)
He said that he was going to office. (I.S.)
Hence, he was at fault is the right usage

likes will replace like because –
When Subjects are joined using as well as, along with, together with, the Verb agrees with the first Subject.
Singular Subject ® Singular Verb (Main Verb + s)
Plural Subject ® Plural Verb (Main Verb without s)
Hence, you likes is the right usage

Correct Option: B

likes will replace like because –
When Subjects are joined using as well as, along with, together with, the Verb agrees with the first Subject.
Singular Subject ® Singular Verb (Main Verb + s)
Plural Subject ® Plural Verb (Main Verb without s)
Hence, you likes is the right usage

stone will replace stones because –
stone is an Uncountable Noun and hence does not have a Plural form.

Correct Option: C

stone will replace stones because –
stone is an Uncountable Noun and hence does not have a Plural form.

poems will replace poetries because –
poetry is used both in Singular and Plural.
poems is the Plural of poem.
Look at the examples given below :
His collection of poems is worth-reading.
There was a poetry reading session last evening.
Hence, no poems is the right usage

Correct Option: B

poems will replace poetries because –
poetry is used both in Singular and Plural.
poems is the Plural of poem.
Look at the examples given below :
His collection of poems is worth-reading.
There was a poetry reading session last evening.
Hence, no poems is the right usage