The correct answer is option 2: 3.

To understand why, let`s consider the concept of electrical combinations with resistances. When we have three equal resistances, we can arrange them in different ways to create different electrical combinations.

Option 1: 2 combinations - This means that we can arrange the resistances in two different ways to create two unique electrical combinations. However, this is not the maximum number of combinations possible.

Option 2: 3 combinations - This is the correct answer. With three equal resistances, we can arrange them in three different ways to create three distinct electrical combinations. For example, we can connect them in series (end to end), in parallel (side by side), or in a combination of series and parallel.

Option 3: 4 combinations - This is incorrect. With three equal resistances, we cannot create four different electrical combinations.

Option 4: 5 combinations - This is also incorrect. With three equal resistances, we cannot create five different electrical combinations.

Therefore, the maximum number of different electrical combinations possible with three equal resistances is three.