Answer: The flowers on the altar were given to the church too late for the morning service; instead, we'll use them in the evening service.
Step-by-step explanation:
Conjunctive Adverbs are adverbs that link independent sentences together. Independent in the sense that they can stand alone. Conjunctive Adverbs are thus a mixture of Adverbs and Conjunctions.
Examples include, thus, instead, also, finally etc.
The first option uses the Conjunction "Instead" to link the two independent sentences "The flowers on the altar were given to the church too late for the morning service" and "We'll use them in the evening service."
Option B used "But" for this purpose which is a Conjunction.