Refer to figures.
Piston Engines have always suffered from icing problems in some of the conditions that aircraft require them to be operated. There are two type of piston engine induction system, they both suffer from induction icing differently.

• Carburettors - The original method for mixing fuel and air prior to the cylinder, the carburettor uses the venturi effect to "suck" fuel out of the tube, into the airstream. For icing considerations, this has two problems; the fuel vaporising requires latent heat to be input, removing heat from the surrounding air, and the low pressure in the venturi (and throttle valve) which further cools the air. In certain conditions, These could make the air colder than 0ºC, and it would then be possible to form ice on the walls of the carburettor, and on the throttle valve, especially at low throttle settings where the throttle valve only has a small gap for the air to pass through, which will cause even lower pressure (annexes above). This is on top of the usual icing that can form, such as on air filters or wherever the air impacts a cold metal surface, similar to airframe icing. Carburettor heat can be used intermittently to provide hot air to the induction system and melt any ice.
• Fuel Injection - A system where the exact amount of fuel is injected into the intake air, either just before the intake valve, or inside the cylinder. As there is no venturi and no fuel evaporation in this system, the usual "carburettor icing" concerns are no longer an issue. However, icing may still form, such as at any bends in the system, or where the air has to impact a cold surface such as the air filter, similar to airframe icing. Fuel icing is also possible (but it is possible in a carburettor system also, so that is not the correct answer). Fuel injected engines have an "alternate air" system which will bypass any such problems if required.

Therefore, from those options, the answer is actually quite simple, ice accretion affects both types of induction system.