:3. A box contains 10,000 flower seeds.  Each seed is known to
grow either a white flower or a red flower.  Four hundred seeds
are drawn at random without replacement and are sown.  121 of
them are observed to produce white flowers.  A 68% confidence
interval for the percentage of white flower seeds in the box is
best given by

 a.  between 28% and 32% 
 b.  between 20% and 40%
 c.  between 25% and 35%
 d.  between 0% and 75%