Prose
क. ६.] चतुर्थोऽध्यायः । ६१७
In plain words
This entry is not a sentence of Śaṅkara's — it is the running head printed at the top of the page: a recension marker, a section number, the words 'Fourth Chapter,' and the page number 617, exactly as a printed book stamps them at the top of every page.
Close to the Sanskrit
[This is not continuous bhāṣya prose but the printed page's running head: the recension marker 'k.', the section marker '6.]', the chapter title 'Fourth Chapter', and the page number '617', as they appear at the top of this page of the 1910 edition.]