[单选题]
The images formed by concag6ke;lh.z6s b ri k12avecxy j;. s9+n;su-4 p sma5nhca lenses
A. are always real.
B. are always virtual.
C. could be real or virtual; it depends on whether the object distance is smaller or greater than the focal length.
D. could be real or virtual, but always real when the object is placed at the focal point.