Which of the statement is true under the normal curve?

Which of the following are true statements?

i. The area under a normal curve is always equal to 1, no matter what the mean and standard deviation are

ii. The smaller the standard deviation of a normal curve, the higher and narrower the graph.

iii. Normal curve with a different means are centered on different numbers.

A. i and ii
B. i and iii
C. ii and iii
D. i, ii, and iii
E. None of the above gives the complete set of true responses.