Answer:
1,2,5
Step-by-step explanation:
I did the assignment
 
        
             
        
        
        
In the base 6 number system, we would only use numerals
from 0 to 5. The idea of base 6 is just like the normal base 10 system, however
instead of using the numerals from 0 to 9, we use numerals from 0 to 5. And
instead of having a ones digit, a tens digit, a hundreds digit and so on, we
use a ones digit, a sixes digit, a thirty-sixes digit, and so on. Therefore in
base 6, the number 321 means 1  one plus
2 sixes plus 3 thirty-sixes, or 121. So to count until 15 for example, we  would need:
 
Base 6                
                                                  Base
10
 
1                      
                                                           1    
2                       
                                                          2
3                      
                                                           3
4                     
                                                            4
5                    
                                                             5
10  (1 six plus 0
ones)                                                 6
11  (1 six plus 1
one)                                                   7
12  (1 six plus 2
ones)                                                 8
13                                                                                9
14                       
                                                      10 
15                       
                                                      11
20  (2 sixes plus 0
ones)                                           12 
21  (2 sixes plus 1
one)                                             13
22                       
                                                      14
23                       
                                                      15
 
        
             
        
        
        
120 different arrangements
        
             
        
        
        
As per the given information;
Bacteria triples every month.
Originally, there were 4 bacterial cells.
We are suppose to find how many there will be after 15 months. 
Hence we can say , the number of bacteria after n month can be given using the exponential growth function
 

So number of bacteria after 15 month will be 

 
        
             
        
        
        
C. Because c is makes more sense