The sentence implies that a major investment bank's adjustment of interest rates on mortgages held by individuals is both a recognition of the depth of the financial crises and an attempt to balance the bank's books.

Option A - correct
This shows correct parallelism between 'a recognition' and 'an attempt' using the word 'both.'

Option B - incorrect
The use of a plural verb 'recognize' for a singular subject 'banks.' Also, the pronoun 'their' books when it should be 'its' books makes the sentence illogical. There is a change of verb form 'is' to 'recognize' and 'attempt.'

Option C - incorrect
This uses improper conjunction to pair 'both' and 'as well as' instead of 'and.'

Option D - incorrect
It changes the intended meaning of the sentence by changing the noun 'adjustment' to a gerund 'adjusting.'

Option E - incorrect
This changes the noun 'adjustment' to a gerund 'adjusting.' Then, it changes the verb from 'is' to 'recognize' and 'attempt,' thereby causing a change in meaning.