The correct option is C 1 - Genus 2 - Species 3 - Strain 4 - Order of isolation
EcoRI comes from Escherichia coli RYB strain. In EcoRI, ‘E’ comes from the genus 'Escherichia'and ‘co’ comes from the species ‘coli’.The letter ‘R’ is derived from the name of the strain RYB. Roman numbers following the names indicate the order in which the enzymes were isolated from that strain of bacteria.