Ingrid and Hubert are jogging through a park, each at a constant speed. When Ingrid started jogging, Hubert had already jogged 200 meters. If Ingrid was jogging faster than Hubert, which one additional piece of information would be needed to determine how long it took Ingrid to catch up to Hubert?
a) Ingrid was jogging at a speed of 6 kilometers per hour
b) Hubert was jogging at a speed of 3 kilometers per hour
c) Their combined speed was 10 kilometers per hour
d) The difference of their speeds was 1 kilometer per hour