The information that the second part of the sentence imparts is that there exists a natural human desire to celebrate and decorate, and to take delight in ornament. If modern architecture is “elaborate”, it would be fulfilling, and not neglecting,this desire. So, “elaborateness; neglects” is wrong.If modern architecture is “austere”, it would be neglecting this natural desire, and not recognizing it. So, “austerity; recognize” is wrong. If modern architecture is “embellishes”, it would again be fulfilling by this natural desire, and not be undermining it. So, “embellishment; undermines” is also wrong. If modern architecture is “severe” (meaning austere), it would be opposing this natural desire. So, “severity; opposes” leads to a logical sentence, and is the correct answer. Sincethere can be no uniformity about decoration or ornamentation, “uniformity; reflects” does not result in a logical sentence.