Which quotation from the "The Oasis: Africa" best supports the idea that the narrator is trying hard to keep going?

“Footsore and weary, but ever before us the pointing finger of the Arab Sheikh, and his ceaseless: ‘On, on.’”

“‘Mohammed!’ I called to my faithful Algerian, ‘I can do no more; I am done!’”

“I was at the end of my tether, racked with fever and aching all over; the heavy, old-fashioned Mauser weighed me down...”

“I shambled along with clouded brain, but every fibre of my body torn with pain and fatigue.”