Correct option is C
Given: each letter is changed to the previous letter in the English alphabetical order
Original word: JUST
J-1=I, U-1=T, S-1=R, T-1=S
New word: ITRS
Vowels: I.
Original word: RIMS
R-1=Q, I-1=H, M-1=L, S-1=R
New word: QHLR
Vowels: None.
Original word: BEST
B-1=A, E-1=D, S-1=R, T-1=S
New word: ADRS
Vowels: A.
Original word: FAST
F-1=E, A-1=Z, S-1=R, T-1=S
New word: EZRS
Vowels: E.
Original word: LOST
L-1=K, O-1=N, S-1=R, T-1=S
New word: KNRS
Vowels: None.
Original word: TIME
T-1=S, I-1=H, M-1=L, E-1=D
New word: SHLD
Vowels: None.
So, 3 words thus formed have a vowel.
Thus, correct option is (c).
Given: each letter is changed to the previous letter in the English alphabetical order
Original word: JUST
J-1=I, U-1=T, S-1=R, T-1=S
New word: ITRS
Vowels: I.
Original word: RIMS
R-1=Q, I-1=H, M-1=L, S-1=R
New word:QHLR
Vowels: None.
Original word: BEST
B-1=A, E-1=D, S-1=R, T-1=S
New word: ADRS
Vowels: A.
Original word: FAST
F-1=E, A-1=Z, S-1=R, T-1=S
New word: EZRS
Vowels: E.
Original word: LOST
L-1=K, O-1=N, S-1=R, T-1=S
New word: KNRS
Vowels: None.
Original word: TIME
T-1=S, I-1=H, M-1=L, E-1=D
New word: SHLD
Vowels: None.
So, 3 words thus formed have a vowel.
Thus, correct option is (c).