NEW NCERT Class 12 history, Ch. 1: All the gold jewelry found at Harappan sites was recovered from hoards. So, second statement is wrong, which eliminated b andd. But then depending on which history book you refer, Harappans were aware or unaware about the horses. So the experts were divided between option a and option c. UPSC chose 'c' as the official answer- meaning Harappans did not know about the horses.