Scientists can use to determine the age of an igneous rock surrounding a fossil.

I think that they can either use fossils or age of rocks

They can use radiometric dating! (:
Basically radiometric dating isn't one hundred percent trust worthy BUT on the bright side is that they do get a general idea of the ages.
I hope all is well, and you pass! Good luck, rockstar! (: I seriously wish you the best!

Your answer is d. silli hope this ! : ) i left an explanation down below if you need it: a sill forms when hot magma squeezes between layers of rock to form a hardened sheet of rock. a sill is basically a tabular sheet intrusion between old layers of sedimentary rock, volcanic beds, or in the direction of foliation inherent in metamorphic rock. the word sill means a concordant intrusive sheet.