(a) A board may grant a classification into Class 3-A for such period of time it deems appropriate but in no event the period exceed one year.

(b) Upon the expiration of a 3-A classification a board shall review any request for an extension of the classification as if it were the first request for that classification, and the fact that the registrant was placed in Class 3-A under apparently similar circumstances will not be a factor in the decision of the board. This section does not relieve a registrant from his duties under § 1621.1 of this chapter.

(c) [Reserved]

(d) A board shall deny a claim for Class 3-A when the evidence fails to meet the criteria established in this part.