Determine whether these statements are true or false.
a.∅ ∈ {∅}
b.∅ ∈ {∅,{∅}}
c.{∅} ∈ {∅}
d.{∅} ∈ {{∅}}
e.{∅} ⊂ {∅,{∅}} f ) {{∅}} ⊂ {∅,{∅}} g) {{∅}} ⊂ {{∅},{∅}}