When palpating the client's abdomen, at which of the following positions should the nurse expect to find the uterine fundus?

The correct answer is D: At the level of the umbilicus. This is where the uterine fundus is typically located at 20 weeks gestation. The fundus rises approximately 1 cm per week until 36 weeks when it reaches the xiphoid process. Choices A and B are incorrect because the uterine fundus should not be located to the right of the umbilicus or 2 cm above it at this stage. Choice C is incorrect as the fundus should be higher than one fingerbreadth above the symphysis pubis by 20 weeks. Thus, the correct position for the uterine fundus at this point in pregnancy is at the level of the umbilicus.