Explanation:

To change the number of the word "mangoes", we need to understand the rules of pluralization in English. Pluralization is the process of changing a word from its singular form to its plural form.

Plural of "mango":
The singular form of the word "mango" is "mango". To make it plural, we need to add the letter "s" at the end. Therefore, the plural form of "mango" is "mangos".

Plural of "mangoes":
The word "mangoes" is already in its plural form. It is the correct plural form of the word "mango". Therefore, the correct answer is option 'D' - Mangoes.

Explanation of other options:
Let's explain the other options and why they are incorrect:

a) Mangos:
This option suggests changing the word "mangoes" to "mangos". While "mangos" is a commonly used form, it is not technically correct. According to the rules of English pluralization, the correct plural form of "mango" is "mangoes". Therefore, option 'A' is incorrect.

b) Mangoes:
This option suggests keeping the word "mangoes" as it is. Since the question asks to change the number of "mangoes", this option is not applicable. Therefore, option 'B' is incorrect.

c) Mengoes:
This option suggests changing the word "mangoes" to "mengoes". However, "mengoes" is not a correct plural form of "mango". The correct plural form is "mangoes". Therefore, option 'C' is incorrect.

Conclusion:
The correct answer is option 'D' - Mangoes. This is the correct plural form of the word "mango".