Concept:“Arch” in “arch rivals” is pronounced /ɑːtʃ/, so the sound tested at the end is /tʃ/.Explanation:A. “splash” ends with /ʃ/, not /tʃ/.B. “patch” ends with /tʃ/, matching “arch”.C. “path” ends with /θ/, not /tʃ/.D. “spark” ends with /k/, not /tʃ/.Answer:B. patch