The U.S. Department of Justice is expected to approve Monsanto Co.’s planned $1.5 billion acquisition of Delta and Pine Land Co. as early as Friday but several key opponents continue to evaluate options to block the deal. Delta and Pine (DPL) operates the largest private cotton seed breeding program in the world, and would give Monsanto, already a global leader in biotech crops, a platform to expand its cotton specialty seeds and genetic traits business.