The correct expression for the rate of the given reaction is

Correct option is C

In the given reaction, OH^- cannot act as a base due to the absence of an acidic hydrogen in the substrate. Therefore, it acts as a nucleophile and attacks the carbonyl carbon. The second step involves the abstraction of an acidic hydrogen by the OH^- ion. The leaving group contains a sp hybridised carbon bearing a negative charge. The sp hybridised carbon having a negative charge is stable to due to its high electronegativity.

The electronegativity of an atom changes depending on the hybridization of the orbital employed in bonding. Electrons in s orbitals are held more tightly than electrons in p orbitals. Hence, a bond to an atom that employs an 

hybrid orbital for bonding will be more heavily polarized to that atom when the hybrid orbital has more s character. That is, when electronegativities are compared for different hybridization schemes of a given element, the order χ(sp³) < χ(sp²) < χ(sp) holds.