Answer: Yours.
The total RRSP contributions you are allowed to make, whether to your own RRSP or a spousal RRSP, are subject to your contribution limit, determined by your earned income from the preceding year plus any contribution room carried forward from previous years. Likewise, you are the one who receives the corresponding income tax deduction.
On the other hand, you can continue making contributions to a spousal RRSP even after you have turned 71 and can no longer contribute to your own plan, as long as you have earned income and your spouse is still under age 71…