If ‘A’ stands for ‘÷’, ‘B’ stands for ‘×’, ‘C’ stands for ‘+’ and ‘D’ stands for ‘−’, then

If ‘A’ stands for ‘÷’, ‘B’ stands for ‘×’, ‘C’ stands for ‘+’ and ‘D’ stands for ‘−’, then what will come in place of the question mark (?) in the following equation?
यदि ‘A’ का अर्थ ‘÷’ है, ‘B’ का अर्थ ‘×’ है, ‘C’ का अर्थ ‘+’ है तथा ‘D’ का अर्थ ‘−’ है, तो निम्नलिखित समीकरण में प्रश्नचिह्न (?) के स्थान पर क्या आएगा?
20 D 8 A 2 C 1 B 5 = ?

22 20 21 23