An expression that can't be reduced further is: a. a value b. a constant c. a variable d. a fundamental

I think it’s b by process of elimination.
a value is just the value of number, fundamental isnt a math term, and variables change so

This is what i found “an explicit formula designates the nth term of the sequence, as an expression of n (where n = the term's location). it defines the sequence as a formula in terms of n. this example is an arithmetic sequence(the same number, 5, is added to each term to get to the next term).” i hope this you for what your looking for. can you plz mark me brainliest?