The one word for the given sentence is 'Espionage. Key Points Let's have a look at the meaning and example of the marked option: Espionage- "The practice of spying or of using spies, typically by governments to obtain political and military information.". (जासूसी करने या जासूसों का उपयोग करने की प्रथा, आमतौर पर सरकारों द्वारा राजनीतिक और सैन्य जानकारी प्राप्त करने के लिए।) E.g: Three people were also accused of engaging in espionage against a rival firm. Let's have a look at the meaning of the other given options: Adjure- "To urge or request someone earnestly or eagerly to do something". (किसी से कुछ करने के लिए ईमानदारी या उत्सुकता से आग्रह करना या अनुरोध करना) Furore- "Public anger or excitement." (जनता का गुस्सा या उत्साह) Expedition- "A short trip made for a particular purpose especially research". (किसी विशेष उद्देश्य विशेष रूप से शोध के लिए की गई एक छोटी यात्रा) Hence, we find that Espionage is the correct one-word substitute for the given meanings. Therefore, the correct answer is Option 4).