Answer: The correct form of the word that completes the sentence is "druggist": "He went to the druggist to get his medication".
Step-by-step explanation: The correct way of spelling the word that fills in the blank is "druggist", that is to say that this word is always written with double "g" and that writing it with just one "g" is considered to be incorrect. Moreover, "druggist" is a noun used to refer to a pharmacist or a professional that prepares and distributes medicinal drugs. In that way, the word "druggist" is formed doubling the consonant "g" and adding the suffix "-ist" at the end of the root word "drug".