4.11—Appearance; testimony; cross-examination.
        
        (a) 
         The applicant shall appear and, except as otherwise provided in  § 4.10,  shall testify at the hearing and may cross-examine witnesses.
    
    
        
        (b) 
         The Secretary and others to whom notice has been sent pursuant to  § 4.7 shall be afforded an opportunity to appear and present evidence and cross-examine witnesses, at any hearing.
    
    
        
        (c) 
         In the discretion of the Commission or presiding officer, other witnesses may testify at the hearing.