The hittites are usually credited as being the first people in southwest asia to have accomplished which of the following?
a. first use of warriors mounted on horseback
b. mastery of iron working techniques
c. invention of the first known writing system
d. development of the first true pastoral society

True blindness may be caused by trauma to the eye, severe conjunctivitis due to  ibr (infectious bovine rhinoceros) or pink eye or other infections, leptospirosis, lead poisoning, selenium toxicity, fungal infections, vitamin a  deficiencies, rabies, vitamin b12 deficiency, neoplastic of the orbit or  conjunctiva, cataracts, congenital malformations, etc. 

The answer to your question is d, i hope this