instruction:
In this task, you're given a context, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both context and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the context or linked information.
question:
Context: n Indiana, where it is illegal to create a historical marker in the "state format" without first getting official approval from that state's historical bureau Link Information: none Answer: none
answer:
How many historical markers does the state of Indiana have?


question:
Context: His doctoral thesis under the supervision of Charles Tart was on the phenomenology of deep states of hypnosis. He subsequently went on to do post-doctoral work in the area of dissociation and hypnosis at Stanford University under David Spiegel. Link Information: none Answer: none
answer:
Which doctorate and post doctorate supervisor's that Cardena worked under was older?


question:
Context: In 1835, Cowper was elected Liberal Member of Parliament for Hertford, Link Information: none Answer: none
answer:

What was the population of Hertford in 1835?