Determine whether the relation r on the set of all people is reflexive, symmetric, antisymmetric, and/or transitive, where (a, b) ∈ r if and only if
a) a is taller than b.
b) a and b were born on the same day.
c) a has the same first name as b.
d) a and b have a common grandparent.

The graph shows the distance y, in inches, a pendulum moves to the right (positive displacement) and to the left (negative displacement), for a given number of seconds x. how many seconds are required for the pendulum to move from its resting position and return? enter your answer in the box.