【单选题】

We often hear the (21) "Bug" while using computers.But what is a bug In computer science, a bug (22) an error in software or hardware. In software, a bug is an error in coding or logic that causes a program to malfunction or to (23) incorrect results. Minor bugs, for example, a cursor that does not behave as (24) -can be inconvenient or frustrating, but not damaging to (25) More severe bugs can cause a program to "hang" (stop responding to (26) and might (27) the user with no (28) but to restart the program, losing whatever (29) work had not been saveD、In (30) case, the programmer must find and correct the error by the (31) known as debugging.Because of the (32) risk to important data, commercial aplication programs are tested and (33) as completely as possible before release. Minor bugs found after the program becomes (34) are corrected in the next update; more (35) bugs can sometimes be fixed with special software, called patches, that circumvents or otherwise (36) its effects.

In hardware, a bug is a recurring (37) problem that prevents a system or set of (38) from working together properly. The (39) of the term reputedly goes back to the early days of computing, when a hardware problem in a computer at Harvard University was (40) to a moth caught between the contacts of a relay in the machine.
A．compounds
B．compositions
C．components
D．composure