Which of the following expressions simplifies to −abcd, where a, b, c and d are real numbers? A. (−a)∙b∙(−c)∙d
B. (−a)∙b∙(−c)∙(−d)
C. a∙(−b)∙(−c)∙d
D. (−a)∙(−b)∙(−c)∙(−d)
I put D and it was incorrect

The average human heart beats 1.15 \cdot 10^51.15⋅10 5 1, point, 15, dot, 10, start superscript, 5, end superscript times per day. there are 3.65 \cdot 10^23.65⋅10 2 3, point, 65, dot, 10, start superscript, 2, end superscript days in one year.how many times does the heart beat in one year? write your answer in scientific notation, and round to one decimal place.

John checked his watch and said that it is thursday, 7 am. what will the day and time be 2006 hours plzzz i will give you 100 points

From the beginning of the day the temperature rose 15 degrees so that by 4 pm it was 87 degrees. what was the temperature at the start of the day