What will cause a nail tip to crack?

Trimming a nail tip with a fingernail clipper can indeed result in a crack due to several factors involved in the process. Nail tips are typically made from a material that is designed for durability but can become weak if they are not handled correctly. When a nail tip is clipped with a fingernail clipper, especially if excessive force is used or if the clipper is not sharp, this can create sharp edges or stress points that may lead to cracking or splitting. Proper technique and tools specifically designed for nail enhancements, like a nail cutter or a file, are generally recommended to avoid damage.

The other options relate to factors that can weaken or damage nails, but they do not specifically lead to cracking when taking into account the context of trimming. Overexposure to moisture can certainly weaken nails and lead to other issues, while excessive pressure can indeed cause breakage, but the act of clipping itself, when done improperly, is directly connected to the cracking of nail tips. Not using a base coat, while detrimental to the longevity and adhesion of polish, does not directly cause cracking in a nail tip, making the act of trimming with a fingernail clipper the correct cause in this scenario.