In the history of ancient India, the Chalukya dynasty was one of the prominent dynasties that ruled over various regions of the Indian subcontinent. The Umayyad Caliphate, on the other hand, was a powerful Islamic empire that existed from the 7th to the 8th century. During their reign, the Umayyad Caliphate launched several invasions in different parts of India, including southern Gujarat.

The correct answer to the question is option 'C' - Vikramaditya II. Vikramaditya II was a notable ruler of the Chalukya dynasty, who ruled from 733 to 746 CE. He succeeded his father, Vijayaditya, and was known for his military campaigns and successful resistance against the Umayyad invaders.

Here is a detailed explanation of the Arab invasions during the reign of Vikramaditya II:

1. Arab Invasions in India:
- The Arab invasions in India began in the early 8th century when the Umayyad Caliphate aimed to expand its empire beyond the Arabian Peninsula.
- The Arabs targeted the rich trading ports of India, including Thana, Broach, and Cambay, to gain control over the lucrative trade routes.

2. Reign of Vikramaditya II:
- Vikramaditya II ascended the throne of the Chalukya dynasty at a time when the Umayyad Caliphate was actively involved in invading Indian territories.
- He ruled from his capital at Kalyani (present-day Basavakalyan in Karnataka) and was known for his military prowess and strategic skills.

3. Arab Invasion of Southern Gujarat:
- During the reign of Vikramaditya II, the Umayyad Caliphate launched an invasion in southern Gujarat, targeting the prosperous port cities.
- The Arab intruders aimed to capture the trade routes and establish their dominance over the region.

4. Resistance by Vikramaditya II:
- Vikramaditya II actively resisted the Arab invaders and successfully defended his kingdom from their attacks.
- He organized a strong military force and employed effective strategies to counter the Arab forces.

5. Outcome of the Invasions:
- Despite the Arab invasions, Vikramaditya II was able to protect his kingdom and maintain the integrity of the Chalukya dynasty.
- The Arab invaders faced significant resistance and were unable to establish a lasting foothold in the region.

Overall, the Arab intruders of the Umayyad Caliphate invaded southern Gujarat during the reign of Vikramaditya II, a prominent king of the Chalukya dynasty. His successful resistance against the invaders ensured the protection of his kingdom and safeguarded the interests of his people.