'Shy' means 'nervous or timid in the company of other people'.
Option A: 'Shy' forms a word with the suffix 'ness': shyness.'Shyness' means 'the quality or state of being shy'.
Hence option A is correct.
Options B, C and D: The words 'shyable', 'shyary' and 'shyible' do not exist in standard English language.
Hence options B, C and D are wrong.