Both options are extreme and equally unpalatable. I really don't know what the prang statistics are like in your country, but in this part of the world (ie not necessarily this particular country), there seems to be a pretty equal spread between CFIT due to "scud running" and deathly spiral dive due to spatial disorientation when trying to fly on instruments. With a total of 10 hours IF in your total flying, I'd say you know just enough to be a real hazard to yourself.
The (a) option might force you to remain in cloud for a very long time and there's no real guarantee that you'll find a hole that's big enough to be useful at the end of that time. A great deal of discipline and concentration is needed for instrument flight and, when you come right down to it, how well is the aeroplane equipped to deal with the situation? Do you know how to use pitot heat and any other anti-icing systems on the aeroplane? Do you know when and how to use carburettor heat, to prevent carby icing?
No, I don't believe that option (a) is a realistic option for you, in this circumstance.
Option (b) demands a high level of knowledge of the terrain all the way along the route, including any diversions necessitated by the weather. You are literally betting your life - and maybe the lives of other people on the ground - that you're not going to prang. And you will undoubtedly still need to know when and how to use the carby heat control.
Both of these scenarios involve prolonged stress. Have you stopped to consider how that could impair your judgement? Both scenarios require a high degree of concentration on keeping the aeroplane's shiny side up. And while you're concentrating on that, you're losing track of your remaining fuel. You could also be losing track of an otherwise effective monitoring of engine instruments that might warn you of other problems... such as carby icing.
I don't wnat to sound like I'm harping on that but, in most of the more elemental single engined aeroplanes, it's one of the major considerations that you need to keep in mind, especially in the situation that you've described.
But you could also be losing your situational awareness because of the need to concentrate on flying the aeroplane. Yes, flying the aeroplane IS the first rule in every situation, but it ain't the only one and it's the lack of attention to detail that is as likely to bring you unstuck.
To my mind, the only logical answer is what you have referred to as the "precautionary landing". Let there be no mistake here, the scenario you've described is an emergency. The landing is, therefore, not precautionary, it is an emergency landing that you are going to make in the first area that you see that looks big enough and solid enough for the purpose.
In all the years I've been flying - and that's quite a few - I've always believed that it's far better to be down on the ground, wishin you were up in the sky, than to be up in the sky wishing you were down on the ground. That latter case produces the loneliest, most helpless feelings imaginable... you can trust me on that.