Refer to figure. 
The chart in this case is largely irrelevant, other than showing higher terrain in the area of the aircraft. Of the four listed errors, only scalloping is associated with the VOR, the rest are generally considered to be errors of the NDB/ADF.

Night effect --> INCORRECT. This is a phenomenon associated with the NDB, not the VOR. It is caused by the ionosphere moving at dusk and dawn and allowing distant NDB signals to reach the aircraft and create erroneous direction indications.

Scalloping --> CORRECT. This is the only error that affects the VOR from the available options. It is a bending of the radio wave by terrain or buildings - in this case, probably terrain.

Fading --> INCORRECT. This is when a receiver picks up two signals with the same frequency, and they in effect cancel each other out. This is unlikely to be happening here as it is again mainly associated with the NDB not the VOR. Also the signal would disappear not fluctuate from side to side.

Mountain effect --> INCORRECT. Mountain effect is the diffraction of radio waves in mountainous terrain and again, is associated with the NDB not the VOR.

VOR scalloping is described as an imperfection or deviation in the received VOR signal. Scalloping causes the signal to bend as a result of site error - reflections from buildings and terrain. Scalloping also causes the Course Deviation Indicator (CDI) to slowly or rapidly shift from side to side. Scalloping has a negative effect on the accuracy of the navigation aids used.

Unlike the NDB, errors in the VOR are limited; scalloping and multipath are generally the only errors listed in the LOs in relation to the VOR.