Give the identity element, if one exists, for each binary operation in the given structure...

Give the identity element, if one exists, for each binary operation in the given structure.

(a) (real numbers, +, *, )

---

(b) (sets, )

---

(c) ({0, 1}, □, , *) as defined in Example

---

(d) (subsets of a finite set A, )

Example

Exercise

Using the definitions in Example, determine if the other possible distributive property holds.