got all my books out and rechecked answers: setting it out in the normal way:-

103 T +4+5+8 = 120 C

223 T -3+4 = 224 C

299 T +3+5+10 = 317 C

109 T +2-8-5 = 098 C

only question 2 provides the correct answer.

You need to get your books out again. You've simply added the deviation and variation without recognising the difference between +5 and 5W

Westerly values can be written as 5W or -5 degrees. Easterly are 5E or +5 degrees. Convert all the numbers your given to E/W format (+4 = 4E) and apply the rule of thumb.

So working forward gives

Q1 = 111 + 8 + 5(West is best) - 4(East is least) = 120

I've no idea where you got the questions from, but how likely is it that 3 out of 4 questions don't give you the correct option...?