How do ideological parties and single-issue parties differ from one another? a. ideological parties tend to be more liberal, while single-issue parties tend to be more conservative. b. ideological parties focus on certain beliefs, while single-issue parties focus on one main concern. c. single-issue parties tend to be more liberal, while ideological parties tend to be more conservative. d. single-issue parties focus on certain beliefs, while ideological parties focus on one main concern.