This is a very simple Swift programming question with a simple solution. Please give the simplest solution possible, as this is just an introduction to iOS programming.

Problem 1: What's wrong with the following code? (1 point) The code snippet does not execute, find the error and correct it. let firstName = "John" if firstName == "John" { let lastName = "Doe" } else if firstName == "Will" { let lastName = "Do" } let fullName = firstName + ' + lastName