Which technique would you select for measuring the sugar concentration in jam?

Correct option is C

A refractometer is the appropriate instrument used to measure the sugar concentration (°Brix) in liquid and semi-liquid foods like jam, fruit juices, and syrups.
It works by measuring the refractive index of a solution, which changes with the concentration of dissolved solids, especially sugars.
The reading is typically expressed in degrees Brix (°Brix), where 1° Brix = 1 gram of sucrose in 100 grams of solution.
This method is rapid, accurate, and widely used in the food processing industry.
Why not other options?
Line spread test: Used to measure the flowability/viscosity of semi-solid foods, not sugar concentration.
Food composition tables: Provide average values but not actual measurements of a specific sample.
Triangle test: A sensory evaluation method to detect differences, not used for sugar quantification.
Hence, the correct answer is Option (c).