The value of old maps as documents useful for historicity depends necessarily on to what degree they depict and on how accurately. For virtually all periods of pre-modern history some maps have survived to serve as historiography, depicting, however imperfectly, certain features of past geography. The work of Claudius Ptolemy-who lived in the $2^{\text {nd }}$ century A.D.-for centuries provided the basis for maps of the known world and its major regions. Although many were drawn on the scientific basis which he provided, they nevertheless embodied many errors-of location, distance, and the shape of areas of land and sea. The medieval Portolan charts of the Mediterranean Sea and the later charts which provided sailing directions, produced in Holland, were accurate enough to be useful in practical navigation. However, few of the early maps approach modern standards, which require accurate representation of distances and of heights above mean sea-level and the use of carefully distinguished symbols. This is because it was not until the 18th century that cartography, as an exact science, was born.

The author of the passage would most likely agree with which of the following?

A. Ancient maps are almost as accurate as modern maps.
B. It is not necessary that a map be completely error free to be useful.
C. Claudius Ptolemy's was the most famous map maker of his era.
D. Cartography is a modern field of study.
E. Information provided by ancient maps is most often incorrect.