It is either the CAA or the CAMO who recommend the ARC revalidation.
There is now a third option for ELA1 aircraft (includes aeroplanes < 1000Kg). For these aircraft, the airworthiness review may be performed by appropriately qualified independent certifying staff for two consecutive years. In this case, the airworthiness review must be performed by a CAMO or by the CAA once every three years. See M.A.901(g)