The book To Save the Earth is so persuasive that no one who reads it can fail to heed its environmentalist message. Members of the Earth Association have given away 2, 000 copies in the last month. Thus the Earth Association can justly claim credit for at least 2, 000 people in one month converted to the environmentalist cause. Which one of the following is an assumption on which the argument depends? ['No other environmental organization gave away copies of To Save the Earth during the month in which the Earth Association gave away its 2, 000 copies.', 'The copies of To Save the Earth given away by members of the Earth Association were printed on recycled paper.', 'Every recipient of To Save the Earth will embrace the environmental program advocated by the Earth Association.', 'None of those who received To Save the Earth from a member of the Earth Association were already committed to the environmentalist cause when they received this book.']