Answer:
The research strategy that is used to demonstrate infant depth perception is called:
B. The visual cliff.
Step-by-step explanation:
The visual cliff is a social study created in 1957 in the USA where the researchers saw if a baby crawls normally on a surface has the capacity to identify the depth in that surface, so, this was located at a certain height, a part of this was normal and the other part is a translucent glass with the mother at the other side of the cliff, in the results, the babies regularly identified the cliff but could crawl on the glass if the mother smile him/her or definitively stop before the cliff if the mother made angry or scared.