Directions: Select the phrase from the options below that should replace the underlined phrase in the sentence to make it grammatically correct. If the sentence is already correct, select 'No correction required' as your answer.
The GPS receiver calculates it's position by analyzing signals from multiple satellites, relying on the speed of light.
1
calculated it's position by analyzing
2
calculating it's position for analyzing
3
calculates its position by analyzing
4
calculate its position in analyzing
5
No correction required