To determine the correct meaning and part of speech for the underlined word "demonstrations," we can analyze the suffix "-ion," which often indicates a noun form in English. We can also consider the context in which "demonstrations" is used—if it relates to protests, showing something, or providing evidence.
Based on this analysis, the best choice is:
c. proofs or supporting evidence; noun
This is because "demonstrations" in a general sense can refer to acts of showing or proving something, aligning it with examples or evidence. However, without specific context, it's also important to consider the use in sentences where demonstrations might also mean public protests. But given the choices, "proofs or supporting evidence" fits well with the noun form of the word.
If there is specific context that indicates a different meaning, please provide that for a more accurate answer.