Latin 1 Help? Please help me on adjectives?

Question

Select the adjective to translate the word in CAPITAL LETTERS.

The sailors will stay on the LARGE island.

magno

magna

magnus

magnis

I thought that island would be insula and that would be in the accusative case as insulam, and because of that, the adjective would be magnam but one of the answer choices reflect that?

Answer 1

in magna insula (ablativus)

Answer 2

HI! is not insula, is peninsula and the adjective should be magna which means big, and in spanish somenthing like luxury so the word should read LOS MARINOS SE QUEDARON (O ESTUVIERON) EN UNA MAGNA ISLA.

Hope this helps.

Answer 3

"on" takes the ablative so it's "magna," with a long mark over the "a"