Which of the following products is formed when n - heptane is passed over `(Al_2O_3+Cr_2O_3)` catalyst at 773K?

Which of the following products is formed when n-heptane is passed over (Al_(2)O_(3)+Cr_(2)O_(3)) catalyst at 773K?

Aromatisation of n-heptane by passing over (Al_(2)O_(3)+Cr_(2)O_(3)) catalyst at 773 K gives

Benzene vapour mixed with air when passed over V_2O_5 catalyst at 775 K give