The position of how many letters will remain unchanged if each of the letters in the word ‘SIGHTED’ is arranged in the English alphabetical order?

Correct — C. Rule: sort the seven letters alphabetically, then compare the sorted string against the original, column by column.

SIGHTED reads S I G H T E D.
Sorted, it reads D E G H I S T.

Positions 3 and 4 match: G stays G and H stays H.

The other five all move — S becomes D, I becomes E, T becomes I, E becomes S and D becomes T.

That leaves two letters unmoved, which is option (c).

Why the others are wrong

• (a)
  None — None overlooks the middle of the word. G is third in SIGHTED and third in DEGHIST, and H is fourth in both.
• (b)
  Three — Three counts one column too many. Position 5 holds T in the word but I in the sorted string, so only positions 3 and 4 agree.
• (d)
  One — One stops at the first match. G at position 3 is not alone, because H at position 4 holds as well.

This item is clerical accuracy, and it is lost by writing the sorted string wrongly rather than by misunderstanding anything.

Write the alphabetical string out in full before you compare. For SIGHTED the letters are D, E, G, H, I, S and T, and only then does a column-by-column check mean anything.

Compare column by column and tick each agreement. The number of ticks is the answer.

Key facts

• SIGHTED sorted alphabetically is DEGHIST.
• G holds position 3 and H holds position 4 in both strings.
• The remaining five letters all move, giving a count of two.

Common traps

• Mis-sorting the letters, most often by dropping G after H.
• Counting a letter that appears in both strings but in different columns.
• Stopping at the first match and answering One.

No directly related past PYQ was found.