以下Swift代码哪项会返回false?
<pre class="prettyprint">func myFunc() -> Bool{ let a:String? = nil let b:String? = "123" return a ?? b != nil }</pre>
<pre class="prettyprint">func myFunc() -> Bool{ guard true else { return true } return false }</pre>
<pre class="prettyprint">func myFunc() -> Bool{ var a = [1,2,3] var b = [1,2,3] return a == b }</pre>
<pre class="prettyprint">func myFunc() -> Bool{ var b:Bool? = true if let b2 = b{ return b2 }else{ return false } }</pre>
