Pitch Lodged in Umpire's Equip @ HP

[isneths]

Here's one I had in a LL game (Williamsport rules)....

With myself being PU, R1 @ 1st, F1 (P) pitches and ball becomes lodged between my chest protector and my arm. R1 advances to second legally. I then call dead ball.

Using Williamsport rules, which of these would have been the correct call?

a] Dead ball, runner back to first (my initial call)
b] Live ball, runner at second (BU interp assuming I was in play)
c] Dead ball, runner awarded second (after discussion w/ my assignor, who would have ruled it ump interference)