James killed Ken by stabbing him from behind. James called his brother-in-law Don and told the latter that he killed Ken. James asked Don to bury the cadaver of Ken to prevent discovery which he did. a. Don is an accessory but is exempt from liability b. Don is an accessory and is liable c. Don is an accessory but excused from liability pursuant to art 22 of the Revised Penal Code d. Don is an accomplice