Final answer:
Caucasoid people are historically connected to the spreading of the Indo-European language family, specifically the Indo-Iranian languages. They likely originated from Eastern Iran and spoke Eastern Iranian languages, as these are related to the broader historical migrations and linguistic influences within the Indo-European speaking groups.
Step-by-step explanation:
Origin of Caucasoid People and Their Languages
The term "Caucasoid" is an outdated anthropological term historically used to describe a broad group of people primarily from Europe, North Africa, the Horn of Africa, Western Asia, Central Asia, and South Asia. The origin of Caucasoid people would correlate with the spreading of Indo-European language families, which also includes the Indo-Iranian languages. According to historical linguistic studies, early Indo-European language speakers began migrating from the Eurasian Steppe north of the Black and Caspian Seas around 3500 BCE. These migrations influenced a significant part of Europe, Anatolia, Iran, and South Asia.
Considering the four options provided, the closest to historical linguistic consensus is that they originated from Eastern Iran and spoke Eastern Iranian languages. These languages are a branch of the larger Indo-Iranian language family, which is a subgroup of the Indo-European family. It is worth noting, however, that historical linguistics is complex and encompasses the migrations and influences over vast periods, so such answers are somewhat simplified representations of extensive processes involving multiple regions and languages.