The correct order of acidity among the following is:

1. CH₂=CH₂ >CH≡CH > CH₃C≡CH > CH₃-CH₃

2. CH≡CH > CH₃-C≡CH > CH₂=CH₂ >CH₃-CH₃

3. CH≡CH > CH₂=CH₂ > CH₃-C≡CH > CH₃-CH₃

4. CH₃-CH₃ > CH₂=CH₂ > CH₃-C≡CH > CH≡CH

The correct order of strengths of the carboxylic acids :-

(a) I>II>III
(b) II>III>I
(c) III>II>I
(d) lI>I>IlI