1. compression a space in which particles have been spread apart 2. periodic energy an oscillating source of energy that repeats itself in a regular way 3. pulse a non-recurrent wave 4. rarefaction a space in which particles have been pushed together

Assume that two parallel arrays have been declared and initialized: healthoption an array of type char that contains letter codes for different healthcare options and annual cost an array of type int. the i-th element of annual cost indicates the annual cost of the i-th element of healthoption. in addition, there is an char variable, best2.write the code necessary to assign to best2 the health option with the lower annual cost, considering only the first two healthcare options. thus, if the values of healthoption are 'b', 'q', 'w', 'z' and the values of annualcost are 8430, 9400, 7050, 6400 your code would assign 'b' to best2 because 8430 is less than 9400 and is associated with 'b' in the parallel array. (we ignore 'w' and 'z' because we are considering only the first two options.)