A Consumer Group Was Interested in Comparing the Operating Time

A consumer group was interested in comparing the operating time of cordless toothbrushes manufactured by two different companies. Group members took a random
Sample of 18 toothbrushes from Company A and 15 from Company B. Each was charged
Overnight and the number of hours of use before needing to be recharged was recorded.
Company A toothbrushes operated for an average of 119.7 hours with a standard deviation of 1.74 hours; Company B toothbrushes operated for an average of 120.6 hours with a standard deviation of 1.72 hours. The t-test for two means is appropriate in this situation because

A) the two companies are dependent.
B) the two companies are independent.
C) the two companies are matched samples.
D) the observations are paired.
E) None of the above.