A magician's stock and trade is getting the audience to focus on one aspect of his demonstration while he is manipulating another. This is most easy with preoperational children, as they are easily fooled with their tendency to:a. be static thinkers.
b. reverse things in their perception.
c. demonstrate centration.
d. equilibrate.

c. demonstrate centration.

Explanation: When an individual seems to be carried away by an event or activity while neglecting other happenings or occurrences in his or her environment. This can be attributed to inability to maintained shared focus on all the segments of a certain activity. Children in the preoperational stage of development usually between 2 to 7 years of age usually exhibit centration, resulting in their tendency to miss out on important details. As with people who indulge in magical stunts, they tend to attach the focus of the audience to a aspect of their demonstration while tweaking the others, thereby individuals who demonstrate centration will be attached to aspect the magician desires while missing out on the manipulative acts.

sentence 1 is a claim, and sentence 2 lists supporting reasons.

o'henry used irony in "the gift of the magi". this tool was essential to developing the story's theme by showing that the couple bought gifts for each other that they could not actually use at the moment. in addition, the author used this fact to show that people of the society should treasure the things they've received from others, because you may never know if they sacrificed their most treasured possession to aquire the gift.