In the word ‘ENVIRONMENT’, if all the consonants are replaced with their immediate previous letter and all the vowels are replaced with their immediate next letter according to alphabetical series, then how many vowels are there in the new word formed after the rearrangement?

The correct option is One.

Let's break down the step-by-step process of transforming the word ENVIRONMENT based on the given rules.

Step 1: Identify the vowels and consonants in the word ‘ENVIRONMENT’
Vowels (A, E, I, O, U): E, I, O, E (Total 4 vowels)
Consonants: N, V, R, N, M, N, T (Total 7 consonants)

Step 2: Apply the transformation rules
1. Replace each consonant with its immediate previous letter in the English alphabetical series.
2. Replace each vowel with its immediate next letter in the English alphabetical series.

Let's transform each letter one by one:
• E (Vowel) → E + 1 = F
• N (Consonant) → N - 1 = M
• V (Consonant) → V - 1 = U
• I (Vowel) → I + 1 = J
• R (Consonant) → R - 1 = Q
• O (Vowel) → O + 1 = P
• N (Consonant) → N - 1 = M
• M (Consonant) → M - 1 = L
• E (Vowel) → E + 1 = F
• N (Consonant) → N - 1 = M
• T (Consonant) → T - 1 = S

Step 3: Write down the new word formed
The new arrangement of letters is: F M U J Q P M L F M S

Step 4: Count the number of vowels in the new word
Let's check each letter of the new word for vowels (A, E, I, O, U):
F, M, U, J, Q, P, M, L, F, M, S

There is only 1 vowel in the newly formed word, which is U.

Therefore, the correct answer is One.