Macintosh Is Trying to Get His Grandson to Learn the Word

Multiple Choice

Macintosh is trying to get his grandson to learn the word "apple." His attempt involves looking at an apple on a tree, making sure that his grandson is also looking, and then saying "apple." Macintosh's effort to teach his grandson is clearly based on

A) ​infant-directed speech.
B) ​the innate orienting response.
C) ​fast-mapping.
D) ​joint attention.