A company can provide more value for its customers by expanding its product line. There are four product line strategies: up$-$selling, down$-$selling, crossing$-$selling, and line filling.

The Kindle Fire case states $$ To expand the use cases for the Kindle product line, Amazon developed a larger version of the device. The $$549$ Kindle DX featured a $10-$inch screen, making it the ideal e$-$reader for displaying figures and tables from textbooks or business documents.$$ Which product line strategy does Amazon use here for developing its Kindle product line?

Group of answer choices

Cross$-$selling

Down$-$selling

Line$-$filling

Up$-$selling