This Graph Shows an Interpretation of Temperatures Based on the Change

Multiple Choice

This graph shows an interpretation of temperatures based on the change in isotopes in ice-core data. This graph implies that:

A) current temperatures are by far the hottest based on this record
B) atmospheric warming started as early as the late 1700s
C) the coolest time period on this data set was from around 1500 to the last part of the 1700s
D) all of these