Final answer:
The correct plural forms for the nouns are Dictators, Phenomena, Alumni, and Formulas or Formulae. English nouns can have irregular plural forms and some nouns appearing as plural are treated as singular in most contexts. Option A, B, C, D.
Step-by-step explanation:
The correct plural forms for the listed nouns are: A. Dictators (no change needed as it is already plural), B. Phenomena (the correct plural form of 'phenomenon'), C. Alumni (already plural, the singular form is 'alumnus' or 'alumna'), and D. Formulas or Formulae (both are accepted plural forms of 'formula').
It's important to note that some nouns have irregular plural forms and do not follow the standard -s or -es suffix rules.
Various words in the English language such as mathematics, politics, civics, and news may appear plural but are often treated as singular nouns, requiring singular verbs in most contexts unless referring to specific instances where a plural verb might be appropriate. Option A, B, C, D.