&optional with &key

[Robert R. Kessler <KESSLER@UTAH-20.ARPA>]

If you provide an &optional followed by &key's, does that mean that
the &optional becomes required?  The examples don't seem to address the
case:

 ((lambda (a &optional (b 3) &key c (d a))
     (list a b c d x))
  1 :c 7)

Is this an error (i.e. a is bound to 1, b is bound to :c and 7 causes
the error), or is a bound to 1, b bound to 3, c to 7 and d to 1.

Bob.
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