The minimum number of unequal forces whose vector sum can be zero is:

Explanation

When it comes to the minimum number of unequal forces whose vector sum can be zero, let's take a look at the options: (a) 1: If we have only one force, its vector sum cannot be zero. So, option (a) is incorrect. (b) 2: With two unequal forces, their vector sum can only be zero if they have the same magnitude but opposite directions. So, option (b) is a possibility. (c) 3: With three unequal forces, it is possible to have their vector sum equal to zero, even if their magnitudes and directions are different. So, option (c) is correct! (d) 4: Having four unequal forces can also result in a vector sum of zero, but it's not the minimum number. So, option (d) is incorrect. Therefore, the correct option is (c) 3.