Final answer:
To solve a combination circuit, using Kirchhoff's laws is the most effective method as it produces independent equations that match the number of unknowns, allowing for accurate problem-solving. so, option a is the correct answer.
Step-by-step explanation:
When trying to solve for a combination circuit, it is best to use Kirchhoff's laws. Kirchhoff's rules generate a set of linear equations that help us find unknown values in circuits, which could be currents, voltages, or resistances. By applying the junction and loop rules, which are based on conservation laws and can be applied not only to resistors and electromotive forces (emfs) but also to other devices like capacitors, it's possible to analyze complex circuits efficiently. This process creates as many independent equations as there are unknowns, allowing for calculation of the necessary values. Using this method, especially in circuits that are too complex for simple Ohm's law and series-parallel techniques, is the most effective strategy.
Other methods, such as focusing on individual resistances or ignoring parallel branches may not always yield correct results, as they do not account for the complexities of a combination circuit. Ohm's law, on the other hand, is integral in the process but is not sufficient by itself for complete circuit analysis.