[单选题]
08.19: Kepler’s Second Law about “sweeping out f4evxzy6f*)9o +x2o +jgsir sequal areas in en0jm* jdnpg 563yy8hoqual time” can be derived most directly from which consd8gypj 3moh n0j *yn56ervation law?
A. energy
B. angular momentum
C. linear momentum
D. mechanical energy
E. mass
