Consider the following ciphertext message

KLHFROPTHI WRECRLEUVH HJXLEIGKSE VGRDILJXKV THIWRECRLH HTMGVXRSI.

We know it was encrypted according to Vigen`ere square, with a keyword of 3 letters.

(a) List all letters in column 1, column 2, and column 3 corresponding respectively to the first, the second, and the third letter of the keyword.

(b) Calculate the index of coincidence for each of the 3 columns.

(c) Determine the three letters of the keyword. Note that the ciphertext letter associated with the plaintext letter e in each column may not be the top letter in such a short message.

(d) Decipher the message.