The error is in part A of the given sentence. Add ‘A’ before ‘Little’ in part A

The given sentence is error free. Hence, option D -No error is the correct answer.

Replace ‘fall’ with ‘Falls’. “Falls” would be correct as State Bank of India is a single organization hence a singular entity, and the Fifth form of Verb (s/es) is used with singular entities.

The error is in part C of the given sentence. Remove ‘the’ before ‘Summer’ in part C.

The error is in part C of the sentence. As the sentence indicates that from this month, U.S. government will begin with its largest effort (means earnest and conscientious activity intended to do or accomplish something) not comfort (a state of being relaxed and feeling no pain) in the wartime. Thus, replace ‘comfort’ with ‘effort’.

Hence, option C is the correct answer.

The given sentence is grammatically incorrect and an error lies in option A. Here, inversion rule (i.e. put the verb before the subject) will be applied as the sentence starts with a negative phrase.  Thus, ‘they did’ should be replaced with ‘did they’.

The sentence is grammatically incorrect and error lies in option C. Here, after the preposition ‘to’, V2 has been used. The verb after "to" should be in its first form i.e. infinitive. Thus, replace ‘took’ with ‘take’.

The usage of ‘more sooner’ is incorrect here.

‘Sooner’ is an adjective in the comparative degree and the usage of ‘more’ before it is redundant. Thus, ‘more’ should be eliminated to make the sentence grammatically correct.

Thus, option B is the correct answer.

The error is because of the usage of ‘many’.

We use ‘much’ for non-countable nouns while ‘many’ for countable nouns. Here, ‘time’ is an uncountable noun, therefore, ‘much’ must be used instead of ‘many’.

Hence, option B is the correct answer.

When two singular nouns joined by 'and' refer to the same person or thing, the pronoun used for them should be 'singular'. Here, Mr Ashish James is both i.e. teacher as well as principal.
Thus, ‘their’ must be replaced with ‘his’ to make a grammatically correct sentence.
Hence, option B is the correct answer.