The parameters needed for a mysql database connect string are
a
host name
b
user name
c
password
d
all of the above

d. All of the above.

Explanation:

The parameters required to for a MYSQL database connect string are as following:-

So  among  the  given  options all of them  are  required  and  those are host name,user name,password.

Hence the answer to this question is option d all of the above.