In a specimen of n type semiconductor, the initial concentration of holes and electrons is pno and nno. When the specimen is subjected to radiation, the hole and electron concentration increase to pn and nn. Then

• A. pn - pno = nn - nno
• B. pn + pno = nn + nno
• C. pn - pno = nno + nno
• D. pn + pno = nn - pno