Answer:
A). Causal effect transition
Step-by-step explanation:
The transition words are described as the words that are employed to connect ideas in a fluent manner. They function as a bridge to ensure the smooth flow of ideas by relating one sentence to the other to show the association.
In the given sentence, the use of the causal effect transition word 'consequently' which shows that how a specific cause brought a particular effect('we are running of resources...efficient'). These causal effect transitions show the reason behind a certain event, action, or idea which is followed by the effect led by that cause. Hence, option A is the correct answer.