formatting - Best way to format if statement with multiple conditions

Question

If you want to some code to execute based on two or more conditions which is the best way to format that if statement ?

first example:-

if(ConditionOne && ConditionTwo && ConditionThree)
{
   Code to execute
}

Second example:-

if(ConditionOne)
{
   if(ConditionTwo )
   {
     if(ConditionThree)
     {
       Code to execute
     }
   }
}

which is easiest to understand and read bearing in mind that each condition may be a long function name or something.

Answer 1

I prefer Option A

bool a, b, c;

if( a && b && c )
{
   //This is neat & readable
}

If you do have particularly long variables/method conditions you can just line break them

if( VeryLongConditionMethod(a) &&
    VeryLongConditionMethod(b) &&
    VeryLongConditionMethod(c))
{
   //This is still readable
}

If they're even more complicated, then I'd consider doing the condition methods separately outside the if statement

bool aa = FirstVeryLongConditionMethod(a) && SecondVeryLongConditionMethod(a);
bool bb = FirstVeryLongConditionMethod(b) && SecondVeryLongConditionMethod(b);
bool cc = FirstVeryLongConditionMethod(c) && SecondVeryLongConditionMethod(c);

if( aa && bb && cc)
{
   //This is again neat & readable
   //although you probably need to sanity check your method names ;)
}

IMHO The only reason for option 'B' would be if you have separate else functions to run for each condition.

e.g.

if( a )
{
    if( b )
    {
    }
    else
    {
        //Do Something Else B
    }
}
else
{
   //Do Something Else A
}