. I'll show you what I mean in a moment with some photographs taken by Peter and Paul Julie. The work of these two photographers has been a very useful source for studying the art produced in the United States from 1896 to the present. Peter and Paul Julie were not artists. But they were a regular part of the New York art theme. They took over a hundred thousand photographs which document the lives and work of thousands of artists. Peter Julie is known as a pioneer in this field of art photography. Georgia O'keefe and other famous artists sought him out to take pictures of their work. His specialty was photographing paintings. His son Paul photographed sculptures.

Some of their most important photos are the ones of works of art that have since been destroyed. One example is a photo that we'll look at today. Would someone get the lights please？ Thanks. This slide is from a photograph of a painting by Edward Hopper called Corn Belt city. The painting was exhibited only two or three times before it was destroyed in a fire. Without the Julie photograph, no visual record of the work would exist.

Although the Julies mostly photographed the work of painters and sculptors, they also occasionally photographed architectural subjects. They did quite a few photos of buildings by John Russell Pope. And we're going to look at one of those next.

What did Peter Julie do for Georgia O'keefe？

A．He photographed her house.

B．He photographed her paintings.

C．He gave her advice on photography.

D．He gave her advice on painting techniques.