Disputes over Deeds: Who owns the plot?

Bro, I'm stuck on this MCQ from CLAT UG and my friend is like, "Kya pata, wrong answer hoga!" So, here's the scenario:

X and Y jointly purchase a plot of land from Z for ₹10 lakhs. The sale deed mentions the joint names of X and Y, but it doesn't specify the shares. The deed also contains a clause stating that it will be governed by the laws of the state where the plot is situated. If the plot is situated in a state where the joint ownership of property is governed by the "Right of Survivorship" rule, who will own the plot after Y's death?

My friend is saying X will own the plot because of the survivorship rule, but I'm like, "Nah, the deed doesn't specify the shares, so it's just joint tenancy with equal shares between X and Y.