Please briefly describe the types of patents represented by the following patent numbers and their legal status.

Item A is the patent contribution number, as follows:

CN country code (China), 1 application category number (invention), 423552 document serial number, and a document category code (invention patent disclosure specification).

Item B is also the patent contribution number, as follows:

CN country code (China), 2 application category numbers (utility model), document serial number 539506, and document category code Y (utility model authorization specification).

Item C is the patent number, as follows:

ZL stands for "patent", 02 stands for application year (2002), 1 stands for patent type (invention), 34209 stands for serial number, and 1 after decimal point is the computer check bit.