Question: Vulpes qiuzhudingi is believed to be the ancestor of which small fox native to the Northern Hemisphere?

Context paragraphs:
Red fox: The red fox ("Vulpes vulpes"), largest of the true foxes, has the greatest geographic range of all members of the Carnivora order, being present across the entire Northern Hemisphere from the Arctic Circle to North Africa, North America and Eurasia.  It is listed as least concern by the IUCN.  Its range has increased alongside human expansion, having been introduced to Australia, where it is considered harmful to native mammals and bird populations.  Due to its presence in Australia, it is included among the list of the "world's 100 worst invasive species".

Buys Ballot's law: In meteorology, Buys Ballot's law (] ) may be expressed as follows: In the Northern Hemisphere, if a person stands with his back to the wind, the atmospheric pressure is low to the left, high to the right.  This is because wind travels counterclockwise around low pressure zones in the Northern Hemisphere.  It is approximately true in the higher latitudes of the Northern Hemisphere, and is reversed in the Southern Hemisphere, but the angle between the pressure gradient force and wind is not a right angle in low latitudes.

Arctic fox: The Arctic fox ("Vulpes lagopus"), also known as the white fox, polar fox, or snow fox, is a small fox native to the Arctic regions of the Northern Hemisphere and common throughout the Arctic tundra biome.  It is well adapted to living in cold environments.  It has a deep thick fur which is brown in summer and white in winter.  Its body length ranges from 46 to , with a generally rounded body shape to minimize the escape of body heat.

Cape fox: The Cape fox ("Vulpes chama"), also called the cama fox or the silver-backed fox, is a small fox.

Ezo red fox: The Ezo red fox ("Vulpes vulpes schrencki") is a subspecies of red fox widely distributed in the northern hemisphere.  They live in Hokkaido, Sakhalin and surrounding islands in Japan.

March: March is the third month of the year in both the Julian and Gregorian calendars.  It is the second month to have a length of 31 days.  In the Northern Hemisphere, the meteorological beginning of spring occurs on the first day of March.  The March equinox on the 20th or 21st marks the astronomical beginning of spring in the Northern Hemisphere and the beginning of autumn in the Southern Hemisphere, where September is the seasonal equivalent of the Northern Hemisphere's March.

Arabian red fox: The Arabian red fox ("Vulpes vulpes arabica") is a subspecies of the red fox native to Arabia, specifically Dhofar and Al Hajar Mountains in Oman and they are also found in UAE, Syria, Jordan, Palestine, and Israel to Saudi Arabia and Yemen.  The Arabian red fox is similar in color to the common red fox.  However, it is more adapted to desert life than its parent species.  The fox's ears are much larger, and its body is much smaller than that of the red fox.

Blanford's fox: Blanford's fox ("Vulpes cana"), is a small fox found in certain regions of the Middle East and Central Asia.

Vulpes qiuzhudingi: Vulpes qiuzhudingi is an extinct species of fox found in the Himalayas.  It was primarily carnivorous.  The fossils, dating from between 5.08 and 3.60 million years ago, were found in the Zanda Basin and Kunlun Mountains of Tibet.  It was named after Qiu Zhuding, a paleontologist from the Chinese Academy of Sciences.  The species is believed to be the ancestor of "Vulpes lagopus", the modern Arctic fox, which would support the "Out of Tibet" theory: namely, that a number of current arctic species trace their ancestry to species originally from the Tibetan Plateau.

June: June is the sixth month of the year in the Julian and Gregorian calendars and the second month to have the length of 30 days. June contains the summer solstice in the Northern Hemisphere, the day with the most daylight hours, and the winter solstice in the Southern Hemisphere, the day with the fewest daylight hours (excluding polar regions in both cases).  June in the Northern Hemisphere is the seasonal equivalent to December in the Southern Hemisphere and vice versa.  In the Northern hemisphere, the beginning of the traditional astronomical summer is 21 June (meteorological summer begins on 1 June).  In the Southern hemisphere, meteorological winter begins on 1 June.

Supporting paragraphs: Vulpes qiuzhudingi Arctic fox
Answer: Arctic fox