Answer:
Infinity
Step-by-step explanation:
The marginal rate of substitution means the consumer has forgone a certain quantity of one item in exchange for another whilst keeping the equal level of utility.
When two items were viewed (tea and scones), a certain amount of tea was forgone in exchange for scones. Now on the indifference curves, where the tea is on the vertical axis and the scones is one the horizontal axis, the marginal rate of substitution (MRS) at this point will be infinity