Final answer:
The client's understanding is indicated by choosing to elevate the head of the bed and avoid spicy foods to prevent heartburn, while also being cautious with the use of antacids and avoiding large meals before bedtime.
Step-by-step explanation:
The correct statement that indicates the client understands the instructions to mitigate heartburn during pregnancy is c) I'll elevate the head of my bed and avoid spicy foods. Elevating the head of the bed utilizes gravity to prevent stomach acid from backing up into the esophagus, which can cause the burning sensation known as heartburn. Moreover, avoiding certain foods like chocolate, fatty foods, peppermint, coffee, and alcoholic beverages, as well as spicy foods, can reduce the risk of gastroesophageal reflux disease (GERD) symptoms, which are more prevalent during pregnancy due to the upward pressure of the growing uterus on the stomach.
Pregnant women are also recommended to eat smaller meals more frequently, rather than large meals, especially before bedtime to prevent the reflux of stomach content. The use of antacids may be recommended to neutralize excess stomach acid and provide relief, but should not be taken with every meal as a preventative measure without prior consultation with a healthcare provider.