A compound 'H' (CHO) undergoes the following reactions: 'H' reacts with hydroxylamine (NHOH) to form a compound 'I', which does not give a positive result with Tollen's test. On treatment with PCC, compound 'H' is converted into compound 'J'. Compound 'J', when reacted with aqueous NaOH, undergoes aldol condensation to form a compound 'K'. Which of the following best describes compound 'H'? A primary alcohol A secondary alcohol A tertiary alcohol An ether