The number of neutrons (n) and protons (p) for four isotopes is given in the table. What are their symbols?

• A. (i) ⁸⁴₃₇Rb
  (ii) ⁸⁵₃₇Rb
  (iii) ⁸⁷₃₈Sr
  (iv) ⁸⁸₃₈Sr
  
• B. (i) ¹²¹₈₄Po
  (ii) ¹²²₈₅At
  (iii) ¹²⁵₈₇Fr
  (iv) ¹²⁶₈₈Ra
  
• C. (i) ⁸⁴₃₄Po
  (ii) ⁸⁵₃₅At
  (iii) ⁸⁷₃₇Fr
  (iv) ⁸⁸₃₈Ra
  
• D. (i) ¹²¹₃₇Rb
  (ii) ¹²²₃₇Rb
  (iii) ¹²⁵₃₈Sr
  (iv) ¹²⁶₃₈Sr
  

Answer: (A)