(1) The umbrella dates back more than 3,000 years to Mesopotamia. (2) That ancient land was located in the Middle East. (3) The Middle East is a hot and sunny part of the world. (4) Royalty there demanded protection from the sun. (5) People developed the umbrella for this purpose. (6) Use of the umbrella as a sunshade then spread to ancient Europe. (7) In fact, if you analyze the origin of the word umbrella, you will see that it reflects the umbrella’s original purpose. (8) Umbrella comes from the Latin word umbra. (9) Umbra means “shade.” (10) Eventually, the Romans used the umbrella to protect themselves from the rain. (11) They used the umbrella to protect themselves from the sun as well. (12) Today, umbrellas are used mainly as raingear. Which is the most effective way to combine sentences 8 and 9?
a.Umbrella meaning “shade,” the word umbrella coming from umbra.
b.Umbrella comes from the Latin word umbra, which means “shade.”
c.Umbrella , coming from the Latin word umbra, meaning “shade.”
d.Umbrella comes from the Latin word umbra, it means “shade.”

Since the noun "umbra" appears in both sentences and functions as the subject in the second one, an effective way to connect the sentences would be by substituting the repeated word for a relative pronoun. Since "umbra" does not refer to a person, we may eliminate the relative pronoun "who" and choose between "that" and "which". Option B does precisely that: it uses the pronoun "which" to substitute "umbra" and connect the sentences:

b. Umbrella comes from the Latin word umbra, which means “shade.”