Final answer:
The most important instruction for a client receiving omeprazole who has difficulty swallowing is to take the medication with a full glass of water, to ease swallowing without compromising the medication's effectiveness. Therefore, the correct option is c.
Step-by-step explanation:
The question pertains to the appropriate administration of omeprazole to a client who has difficulty swallowing. The correct instruction to provide to a client in this context is to take the medication with a full glass of water. Crushing, chewing, or mixing the medication can affect its efficacy, especially since omeprazole is typically available in a delayed-release form designed to protect the medicine from being broken down by stomach acid before it reaches the intestines.
Therefore, the most important instruction would be:
Take the medication with a full glass of water (C)
Taking omeprazole on an empty stomach is also important for its effectiveness, but in the context of difficulty swallowing, ensuring the medication is taken with enough water to facilitate swallowing is crucial.