Ygdftnjregwyt5khu awnser this pls my brothers work he needs help

Multiplying an even number of negative numbers gives an answer that is choose from:

He amount of carbon-14 present in animal bones t years after the animal's death is given by p(t)equals=upper p 0 e superscript negative 0.00012097 tp0e−0.00012097t. how old is an ivory tusk that has lost 26% of its carbon-14?

Ling listed all of the factors of a mystery number: 1,2,4,8,16,32 what is the mystery number?