The sentence requires understanding the difference between the words 'complement' and 'compliment'.

Understanding Word Meanings

• Complement: This word means to add to something in a way that enhances or improves it; to complete it. It can also mean to go well with something. For example, "The wine complements the meal."
• Compliment: This word means to praise or express admiration for someone or something. For example, "She complimented him on his new tie."

Analyzing the Sentence

The sentence is: "The dress ________ her so well that they all immediately __________ her on her appearance."

• First blank: "The dress ________ her so well" indicates that the dress enhanced her or looked good on her. The word that fits this meaning is complement. So, the past tense form used here is complemented.
• Second blank: "they all immediately __________ her on her appearance" indicates that they praised her looks. The word that fits this meaning is compliment. So, the past tense form used here is complimented.

Filling the Blanks

Based on the analysis, the correct words to fill the blanks are 'complemented' and 'complimented'.

The completed sentence reads: "The dress complemented her so well that they all immediately complimented her on her appearance."

This matches Option D.