  c -  ava (pruval  )  concen- trated    concen- trated  ava concen- trated   ipv  c –  ava (pruval  ).   186.        ( ) /  a     187.    top  avas   ava    ava        ( ) /    c. 188.  top  avas,   avas. 189.   top   avas       (a)     ( )     ( ) / 190.      ava       a        avas,         .      (  ,  ,  ,  )    ir –    –  cr –  eq –  co –                     (a)     ( )     ( ) /               (a)     ( )     ( ) /      please           ‘    ’, ‘    ’   ‘  ’.    please           ‘pv01; eur          ’.            (b)     ( )     ( ) / ava  ava   ( )     ( ) /      calibrate    ipv         (‘ipv  ’)   closest         ( )     ipv     ipv  .