4. Each of the following paragraphs is supposed to have five (5) sentences, which form a complete historical narrative. One of the sentences is missing. Identify the missing sentence from the sentences listed below each paragraph. The sentences are labelled A to E. Write the letter of the missing sentence beside the item number.
(i) 1. The art of making iron was one of the great discoveries, which shaped man's social and economic development.
2. Those who involved themselves in that industry were called blacksmiths.