एक भाषा परीक्षण आरेख में, तीन प्रतिच्छेदी वृत्त क्रमशः भाषा A, भाषा B और भाषा C बोलने वाले लोगों को दर्शाते हैं। यदि केवल एक भाषा बोलने वाले क्षेत्रों को C, A और B के रूप में लेबल किया गया है, तो कौन सा व्यंजक उन लोगों की पहचान करता है जो केवल एक ही भाषा बोल सकते हैं?

In a Venn diagram consisting of a rectangle, a circle, and a triangle, if the region enclosed by both the rectangle and the circle but not by the triangle is labeled with a specific number, and that number is 4, which option correctly identifies this value?

In a certain Venn diagram representing professional and demographic categories, if a triangle represents doctors, a rectangle represents women, and a circle represents postgraduates, which region representing the intersection of all three shapes gives the total number of postgraduate female doctors as 15?