 
<translate> Lambobin harafi 3 = 26 ^ 3; Lambobin harafi 4 = 26 ^ 4; Lambobin harafi 5 = 26 ^ 5; Jimlar = 26 ^ 3 + 26 ^ 4 + 26 ^ 5 = 26 ^ 3 (a cikin 1 + 26) + 26 ^ 5 = 26 ^ 3 * 27 + 26 ^ 5. Amsar ƙarshe: (D). <eng> 3-letter codes = 26^3;
4-letter codes = 26^4;
5-letter codes = 26^5;
Total = 26^3 + 26^4 + 26^5 = 26^3(1+26) + 26^5 = 26^3*27 + 26^5. The final answer: (D). 