What does the word

"unceremoniously" mean in
these sentences?
From my table I go towards a picture which is placed in the corner: thence i set out in an oblique direction for the door; and then although on starting I had intended to return to my table,yet, if I chance to fall in with my arm-chair on the way, I at once, and most unceremoniously, take up my quarters therein....In long winter evenings it is stretch yourself therein, far from the bustle of crowded assemblies
A. exhaustedly
B. elegantly
C. frustratedly
D. casually

PLS helpp