Choose the best Java data type

Which of the following would be the best data type for a variable to store the number of passengers on an airplane?

a$)$ none of these

b$)$ double

c$)$ char

d$)$ String

e$)$ float

f$)$ int

g$)$ boolean

Which of the following would be the best data type for a variable to store a person's height in meters?

a$)$ int

b$)$ float

c$)$ boolean

d$)$ char

e$)$ byte

f$)$ String

Declare a variable of a specified primitive type

Which of the following correctly declares a variable of type boolean in Java? Choose all that apply.

a$)a=$ boolean$($true$)$;

b$)$ boolean$[]a=$ new boolean$[3]$;

c$)$ boolean a;

d$)$ none of these

e$)$ boolean $a=$ new boolean$()$;

f$)$ boolean$[a=0$;

g$)$ boolean $a=$ false;

Write a line of Java code that will declare a double variable named $x$ that is initialized to the value $90\mathrm{.}24.$