The correct answer is B. Burden.
A burden is something that is difficult or unpleasant to carry or bear. It can be a physical burden, such as a heavy load, or an emotional burden, such as a difficult task or responsibility.
A disturbance is an interruption or disruption of peace or order. It can be caused by something physical, such as a loud noise, or something emotional, such as an argument.
A distraction is something that draws attention away from something else. It can be a physical distraction, such as a bright light, or an emotional distraction, such as a thought or worry.
A diversion is a change of direction or activity. It can be a physical diversion, such as a detour, or an emotional diversion, such as a hobby or pastime.
In the context of the question, the word “encumbrance” is used to describe something that is a burden or a hindrance. The correct answer is therefore B. Burden.