The correct option is B 18.84 cm
In 60 minutes, the minute hand of a watch completes one revolution. Therefore, in 45 minutes, the minute hand turns through 4560=34 of one revolution.
∴ θ=34×360∘=270∘=3π2 rad
Hence, the required distance travelled is given by
l=r θ=4×3π2 cm=18.84 cm