Which sentence does not contain any errors in punctuation or capitalization?

a.
the doctor performed cpr on the patient.

b.
the doctor performed cpr on the patient.

c.
the doctor performed c. p.r. on the patient.

d.
the doctor performed c. p.r. on the patient.

What do the excerpts have in common? both point out the tragic nature of situations in which children make journeys without their parents. both describe what immigrant children must do to survive when traveling to the united states. both explain why most children want to leave central america without their parents. both indicate the tragic problems and their consequences that children in central america must face.